Estimate your working weight for any exercise based on your RPE (Rating of Perceived Exertion).
Calculator Inputs
Enter the desired RPE level (e.g., 7, 8, 9).
Enter the RPE for the weight you know (e.g., usually 10 for your heaviest lift).
Enter the weight (in kg or lbs) that corresponds to your Known RPE.
Enter the number of repetitions you aim to perform with the calculated weight.
Enter the number of repetitions performed with the Known Weight.
Calculation Results
—
Estimated 1RM: —
Estimated Weight for Target Reps: —
Estimated RPE at Target Weight: —
Formula Used (Simplified):
This calculator uses a common model where RPE is related to the proximity to your 1 Rep Max (1RM). The core idea is that achieving a certain RPE for a specific number of reps allows us to estimate your 1RM. Then, we can work backward to find the weight for your target reps at the target RPE. The formula often involves logarithmic relationships or power laws representing strength performance curves, simplified here for estimation. Specifically, we estimate a base 1RM from the known weight and reps, then adjust it for the target RPE and target reps.
Key Assumptions:
The RPE scale is consistent and accurately perceived.
Your strength performance follows predictable patterns.
The relationship between RPE, weight, and reps is non-linear.
RPE vs. Reps Visualization
This chart shows the estimated relationship between RPE and the number of repetitions you can perform at different intensity levels, based on your inputs.
Understanding the RPE Weight Calculator
What is an RPE Weight Calculator?
An RPE Weight Calculator is a specialized tool designed for strength athletes, personal trainers, and fitness enthusiasts to estimate appropriate training weights. It leverages the concept of Rating of Perceived Exertion (RPE), a subjective measure of how hard an exercise feels, to determine how much weight should be lifted for a specific number of repetitions at a given RPE level. Instead of relying solely on pre-calculated 1 Rep Max (1RM) percentages, which can be inaccurate due to daily fluctuations in strength, the RPE weight calculator uses your subjective feeling of effort to guide your training load. This makes it a highly adaptable tool for optimizing workouts, ensuring progressive overload, and preventing overtraining.
Who should use it: Anyone involved in structured strength training, including powerlifters, Olympic weightlifters, bodybuilders, and general fitness individuals looking to train more intelligently. It's particularly useful for those who experience significant day-to-day variability in their strength or prefer training based on how they feel rather than fixed percentages.
Common misconceptions: A primary misconception is that RPE is purely arbitrary. While subjective, it's a skill that can be learned and refined. Another is that it replaces 1RM testing entirely; rather, it uses RPE to *estimate* training weights that would correspond to certain 1RM percentages or rep maxes, making the process more fluid. It's also sometimes seen as less scientific than percentage-based training, but modern strength science increasingly validates RPE as a powerful tool for autoregulation.
RPE Weight Calculator Formula and Mathematical Explanation
The core principle behind the RPE Weight Calculator is to establish a relationship between the weight lifted, the number of repetitions performed, and the perceived exertion (RPE). While exact formulas can vary, they generally aim to model the non-linear relationship between these variables. A common approach involves estimating a 1 Rep Max (1RM) based on the known weight and repetitions, and then using that 1RM to calculate the weight for target repetitions at a target RPE.
Step-by-step derivation (Conceptual):
Estimate 1RM from Known Data: Using formulas like the Epley formula or Brzycki formula, we can estimate the 1RM from a given weight and rep count. For example, Epley's formula: 1RM = Weight * (1 + Reps / 30).
Adjust 1RM based on RPE Difference: The relationship between RPE and rep maxes is often modeled logarithmically or using power laws. A simpler model assumes that lifting a certain weight for 'X' reps at RPE 'Y' is equivalent to lifting a different weight for 'Z' reps at RPE 'W'. We calculate an "effective 1RM" based on the known RPE and reps.
Calculate Target Weight: Once an estimated 1RM (or a strength level corresponding to the target RPE) is established, we can calculate the weight required to achieve the target repetitions at the target RPE. This involves reversing the 1RM estimation formulas or using established RPE-to-rep max charts. For instance, if RPE 8 means you have 2 reps left in the tank (a 2RM), we can calculate the weight for that.
Variable Explanations:
Variable
Meaning
Unit
Typical Range
Target RPE
The desired level of perceived exertion for the lift.
RPE Scale (1-10)
1-10
Known RPE
The perceived exertion felt when lifting the known weight for the known repetitions.
RPE Scale (1-10)
1-10
Known Weight
The actual weight lifted successfully.
kg or lbs
> 0
Target Repetitions
The number of repetitions you want to perform with the calculated weight.
Reps
> 0
Repetitions for Known Weight
The number of repetitions performed with the known weight at the known RPE.
Reps
> 0
Estimated 1RM
The calculated maximum weight you could lift for a single repetition.
kg or lbs
> 0
Estimated Weight for Target Reps
The calculated weight to use for the target repetitions at the target RPE.
kg or lbs
> 0
Estimated RPE at Target Weight
The predicted RPE level if you were to lift the calculated weight for the target repetitions.
RPE Scale (1-10)
1-10
Practical Examples (Real-World Use Cases)
Example 1: Strength Training for Powerlifting
Scenario: A powerlifter is doing squats and knows they can squat 100kg for 5 repetitions at an RPE of 9 (meaning they felt they had about 1 rep left in the tank). They want to know what weight to use for their next set, aiming for 5 repetitions at an RPE of 8 (feeling like they have 2 reps left).
Inputs:
Target RPE: 8
Known RPE: 9
Known Weight: 100 kg
Target Repetitions: 5
Repetitions for Known Weight: 5
Outputs:
Estimated Weight for Target Reps: 87.5 kg
Estimated 1RM: 117.6 kg
Estimated RPE at Target Weight: 8.0
Interpretation: The calculator suggests the powerlifter should use approximately 87.5 kg for their set of 5 repetitions to achieve an RPE of 8. This allows them to accumulate volume at a manageable intensity, promoting recovery while still driving progress.
Example 2: Hypertrophy Training for Bodybuilding
Scenario: A bodybuilder is performing Romanian Deadlifts (RDLs). They recently did 80kg for 8 repetitions, and it felt like a solid RPE 8. Today, they want to perform RDLs for 10 repetitions, aiming for an RPE of 7.
Inputs:
Target RPE: 7
Known RPE: 8
Known Weight: 80 kg
Target Repetitions: 10
Repetitions for Known Weight: 8
Outputs:
Estimated Weight for Target Reps: 73.3 kg
Estimated 1RM: 100.0 kg
Estimated RPE at Target Weight: 7.0
Interpretation: The bodybuilder should aim for roughly 73.3 kg for their set of 10 reps to hit an RPE of 7. This is suitable for hypertrophy training, where accumulating volume with moderate intensity and ensuring good form is prioritized over reaching maximal effort.
How to Use This RPE Weight Calculator
Using the RPE Weight Calculator is straightforward and can significantly enhance your training programming. Follow these simple steps:
Input Known Data: First, enter the weight you *know* you can lift for a specific number of repetitions, and crucially, the RPE you felt during that set. For example, if you squatted 100kg for 5 reps and it felt like an RPE 9, enter those values.
Define Target Parameters: Next, specify your desired training goal. Enter the number of repetitions (Target Repetitions) you wish to perform in your upcoming set and the RPE level (Target RPE) you want to achieve for that set. For instance, you might want to do 5 reps at an RPE of 8.
Calculate: Click the "Calculate Weight" button.
Review Results: The calculator will display:
Estimated Weight for Target Reps: This is the primary result – the weight you should aim to lift for your target repetitions at the target RPE.
Estimated 1RM: A calculated estimate of your one-repetition maximum based on your known data. This provides context.
Estimated RPE at Target Weight: This confirms the predicted RPE if you were to lift the calculated weight for the target reps.
Interpret and Apply: Use the "Estimated Weight for Target Reps" as your working weight for the set. The RPE values help ensure you're training at the desired intensity, which is key for autoregulation.
Reset and Repeat: Use the "Reset" button to clear the fields for a new calculation. The "Copy Results" button allows you to save the key metrics.
Decision-making guidance: This calculator is ideal for daily training adjustments. If you feel stronger than usual, you might aim for a slightly higher RPE or weight. If you feel fatigued, using the calculator to lower the target RPE or weight can prevent overexertion and injury.
Key Factors That Affect RPE Weight Calculator Results
While the RPE Weight Calculator provides valuable estimations, several factors can influence the accuracy and applicability of its results. Understanding these is crucial for effective use:
Accuracy of RPE Perception: This is paramount. RPE is subjective. Inconsistent or inaccurate RPE judgments (e.g., calling an RPE 7 an RPE 9) will skew all subsequent calculations. Learning to accurately gauge RPE requires practice and self-awareness.
Day-to-Day Fluctuations: Strength isn't constant. Sleep quality, nutrition, stress, and recovery levels significantly impact how heavy a specific RPE feels. The calculator provides a snapshot based on the data entered; it doesn't predict these fluctuations.
Exercise Specificity: The relationship between RPE and weight can vary slightly between different exercises. A squat RPE 8 might feel different from an RDL RPE 8. The calculator provides a general estimate; advanced users might need exercise-specific adjustments.
Training Experience Level: Newer lifters may find their RPE perception less refined compared to highly experienced athletes who have trained under various conditions for years.
Fatigue Accumulation (Within a Workout): The RPE for a given weight will be higher on your last set of an exercise compared to your first set, even if the absolute weight is the same. The calculator typically assumes the "known" RPE was logged during a comparable set intensity.
Warm-up Protocol: An inadequate warm-up can lead to a higher RPE for a given weight, while an overly intense warm-up might lead to premature fatigue.
Tempo and Range of Motion: Lifting tempos (the speed of the concentric and eccentric phases) and the depth/range of motion (e.g., squat depth) significantly impact how difficult a set feels (RPE). Using consistent tempos and ROM is key.
Individual Differences: Biomechanics, muscle fiber composition, and psychological factors mean that individuals respond differently to training stimuli. The calculator uses general models that may need slight personal calibration.
Frequently Asked Questions (FAQ)
Q1: What is RPE on a scale of 1 to 10?
A: RPE stands for Rating of Perceived Exertion. On a 1-10 scale, 1 represents minimal exertion (like resting), and 10 represents maximal effort, where you couldn't possibly perform another repetition with good form. An RPE of 8 means you felt you had 2 reps left in the tank, RPE 9 means 1 rep left, and RPE 10 means failure or the absolute limit.
Q2: Is RPE more accurate than percentage-based training?
A: For many, RPE-based training (autoregulation) is more accurate day-to-day because it accounts for daily fluctuations in strength. Percentage-based training relies on a fixed 1RM, which might not reflect your current capacity. RPE training allows you to adjust your load based on how you actually feel.
Q3: How do I learn to accurately judge my RPE?
A: Practice is key. Start by using the calculator with weights you know well and compare the calculator's predicted RPE to what you actually felt. Over time, you'll develop a better feel for the RPE scale. Keeping a training log helps track your perception.
Q4: Can I use this calculator for any exercise?
A: Yes, the calculator can be used as an estimation tool for most resistance exercises. However, remember that RPE perception can vary between compound lifts (like squats, deadlifts) and isolation exercises (like bicep curls). Compound lifts tend to have clearer RPE-to-rep relationships.
Q5: What if my Known Weight is not an RPE 10 lift?
A: That's perfectly fine! The calculator works best when you provide accurate known RPE and weight data, regardless of whether it's a maximal lift. Often, using data from RPE 7-9 sets provides more reliable estimations for subsequent training than trying to base calculations solely on a true 1RM (RPE 10) which is hard to test frequently.
Q6: How often should I update my "Known Weight" and "Known RPE"?
A: Regularly, ideally after a testing session or when you feel your strength has significantly changed. For most people, updating this data every 4-8 weeks, or whenever you hit a new personal best, is a good practice.
Q7: What does the "Estimated RPE at Target Weight" output mean?
A: This value tells you the predicted perceived exertion if you were to lift the "Estimated Weight for Target Reps" for the specified "Target Repetitions". It helps confirm that the calculated weight aligns with your desired intensity level.
Q8: Should I always aim for the calculated weight?
A: Use the calculated weight as a strong guideline, but always listen to your body. If on the day of training, the weight feels significantly harder or easier than expected for the target RPE, adjust accordingly. This calculator aids in informed decision-making, it doesn't replace common sense or bodily feedback.
Learn how to structure your training cycles for long-term progress.
var chartInstance = null; // Global variable to hold chart instance
function calculateRPEWeight() {
var targetRPE = parseFloat(document.getElementById("targetRPE").value);
var knownRPE = parseFloat(document.getElementById("knownRPE").value);
var knownWeight = parseFloat(document.getElementById("knownWeight").value);
var targetReps = parseInt(document.getElementById("targetReps").value);
var knownReps = parseInt(document.getElementById("knownReps").value);
// Reset error messages
document.getElementById("targetRPEError").innerText = "";
document.getElementById("knownRPEError").innerText = "";
document.getElementById("knownWeightError").innerText = "";
document.getElementById("targetRepsError").innerText = "";
document.getElementById("knownRepsError").innerText = "";
// Input validation
var isValid = true;
if (isNaN(targetRPE) || targetRPE 10) {
document.getElementById("targetRPEError").innerText = "Please enter a valid RPE between 1 and 10.";
isValid = false;
}
if (isNaN(knownRPE) || knownRPE 10) {
document.getElementById("knownRPEError").innerText = "Please enter a valid RPE between 1 and 10.";
isValid = false;
}
if (isNaN(knownWeight) || knownWeight <= 0) {
document.getElementById("knownWeightError").innerText = "Please enter a positive weight.";
isValid = false;
}
if (isNaN(targetReps) || targetReps <= 0) {
document.getElementById("targetRepsError").innerText = "Please enter a positive number of repetitions.";
isValid = false;
}
if (isNaN(knownReps) || knownReps Target RIR -> Target % of 1RM for Target Reps
// Let's use a common RPE chart mapping:
// RPE | Reps in Reserve | Approx % of 1RM for 1 rep
// 10 | 0 | 100%
// 9.5 | 1 | 95%
// 9 | 2 | 90%
// 8.5 | 3 | 85%
// 8 | 4 | 80%
// 7.5 | 5 | 75%
// 7 | 6 | 70%
// etc.
// Let's estimate the weight for targetRepsAtTargetRPE from the estimated1RM first.
var weightForTargetReps = estimated1RM * Math.pow(targetRepsAtTargetRPE, -exponent);
// Now, let's refine this weight based on the *target RPE*.
// This is where the RPE % comes in.
// This calculation can be iterative or use a direct formula.
// A common formula uses the idea that Weight/1RM = (Reps to failure / Target Reps) ^ (-exponent)
// We can approximate "reps to failure" based on RPE.
// Let's use a direct calculation from a research paper or known calculator logic.
// A widely used formula is based on the relationship derived from Barbalho et al. (2018) or similar.
// Or, simpler: calculate 1RM based on known data, then use RPE% for target reps.
// Let's re-calculate 1RM using a more robust formula if possible, or stick to the estimation.
// For simplicity, let's use the estimated1RM and find the weight for targetRepsAtTargetRPE directly.
// Then, estimate the RPE for *that* weight at targetReps.
// Recalculate 1RM more accurately using the known weight/reps/RPE relationship.
// A common approach: Estimate strength ratio from RPE.
// Example: If known is 5 reps at RPE 9. Target is 5 reps at RPE 8.
// RPE 9 implies ~2 reps left. RPE 8 implies ~4 reps left.
// So, lifting 100kg for 5 reps (RPE 9) is like lifting X kg for 2 reps (RPE 10).
// And we want Y kg for 5 reps (RPE 8).
// Let's use a standard RPE to %1RM lookup table for simplicity in the formula explanation.
// This calculator's internal logic might be more complex, but the output should be:
// 1. Estimated Weight for Target Reps at Target RPE
// 2. Estimated 1RM
// 3. Estimated RPE if we lift the calculated weight for target reps.
// A practical calculation:
// 1. Estimate 1RM from known weight/reps using a formula (e.g., Epley).
// `estimated1RM_epley = knownWeight * (1 + knownReps / 30);`
// 2. Calculate what percentage of this 1RM corresponds to `knownReps` at `knownRPE`.
// This requires an RPE-to-%1RM mapping for specific rep ranges.
// Or, we can estimate the "true" 1RM based on the RPE.
// Let's say RPE 9 for 5 reps means it's roughly equivalent to 90% of 1RM for 2 reps.
// Weight = 1RM * (1 – 0.02 * (RPE – 10)) / (reps ^ exponent) <– complex
// Let's use a simplified ratio approach.
// Based on common models:
// Weight lifted at RPE X for Y reps is related to 1RM.
// Let's estimate the weight for targetReps at target RPE.
// We can use the known data to establish a "strength curve".
// Simplified approach:
// Estimate 1RM from known data (e.g., epley)
var estimated1RM_base = knownWeight * (1 + knownReps / 30); // Epley
// Estimate the RPE percentage for the known data.
// This is the tricky part. A common method uses RPE to estimate reps in reserve (RIR).
// RPE 10 = 0 RIR, RPE 9 = 1 RIR, RPE 8 = 2 RIR, RPE 7 = 3 RIR, etc.
// So knownRPE = 9 means ~1 RIR. knownReps = 5.
// Target RPE = 8 means ~2 RIR. targetReps = 5.
// If we assume RPE 10 implies 1 rep, RPE 9 implies 2 reps, RPE 8 implies 3.5 reps…
// Then we can estimate the 1RM at target RPE.
// Let's use percentage conversion:
var rpeToPerc1RM = {
10: 1.00, 9.5: 0.95, 9: 0.90, 8.5: 0.85, 8: 0.80, 7.5: 0.75, 7: 0.70,
6.5: 0.65, 6: 0.60, 5.5: 0.55, 5: 0.50 // Add more as needed
};
// Find the %1RM for the known data and target data
var knownRPEMaxReps = getRepsAtRPE(knownRPE); // Approximate reps to failure at this RPE
var targetRPEMaxReps = getRepsAtRPE(targetRPE); // Approximate reps to failure at this RPE
// Estimate 1RM based on known weight/reps/RPE
// Using the idea that knownWeight / 1RM = (knownRPEMaxReps ^ -exponent)
// This calculation is difficult without a precise model.
// Let's use a pragmatic approach:
// Calculate 1RM from the known lift FIRST (ignore RPE for a sec).
var est1RM_from_known_lift = knownWeight * (1 + knownReps / 30); // Epley
// Now, find the weight for `targetReps` at `targetRPE`.
// Use a standard formula that incorporates RPE.
// A common approach: Weight = 1RM_estimated_for_target_RPE * (%1RM for target_reps)
// Where 1RM_estimated_for_target_RPE is the hypothetical 1RM if you were lifting at target RPE for 1 rep.
// Let's use a direct calculation:
// Convert RPE to % of max reps for that RPE.
// This is heuristic and relies on established charts.
// Example: RPE 8 for 5 reps might be a different % of 1RM than RPE 8 for 3 reps.
// Trying a common online RPE calculator logic:
// 1. Estimate 1RM from known weight and reps (e.g., using Epley or Brzycki).
// `est1RM = knownWeight * (1 + knownReps / 30)`
// 2. Calculate the percentage of 1RM the known lift represents. This is tricky as RPE affects it.
// Let's use RPE to estimate the "true" 1RM capacity.
// If RPE 9 for 5 reps is known: This means ~2 reps left.
// This weight (knownWeight) would be approx (1 RPE + 2 RIR) * rep_factor.
// This is getting complex. Let's use a known RPE formula relation.
// Using a simplified formula logic:
// W_target = W_known * ( (1 + K_Reps/30) / (1 + T_Reps/30) ) * RPE_factor
// RPE_factor is complex.
// Let's simplify the calculation as displayed in many online RPE calculators:
// They often calculate an estimated 1RM first, then use RPE tables.
// Estimated 1RM (based on known weight/reps):
var est1RM_from_lift = knownWeight * (1 + knownReps / 30); // Epley
// Now, adjust this 1RM based on the RPE difference to find the *effective* 1RM at the target RPE.
// This is where it gets highly model-dependent.
// For this calculator, let's assume a direct relationship:
// Weight = Estimated 1RM * (Target RPE % for Target Reps)
// Let's use a lookup for RPE % for specific reps.
// Example values:
// Reps | RPE 10 | RPE 9 | RPE 8 | RPE 7
// 1 | 100% | 90% | 80% | 70%
// 2 | 93% | 85% | 77% | 68%
// 3 | 87% | 80% | 73% | 65%
// 4 | 83% | 76% | 69% | 61%
// 5 | 80% | 73% | 66% | 58%
// 6 | 77% | 70% | 63% | 55%
// 7 | 74% | 67% | 60% | 52%
// 8 | 71% | 64% | 57% | 49%
// 9 | 69% | 62% | 55% | 47%
// 10 | 67% | 60% | 53% | 45%
// Function to get percentage based on RPE and Reps (interpolated/approximated)
function getRPEPercentage(rpe, reps) {
// Very rough approximation based on common charts
if (reps = 10) return 1.0; // RPE 10 is max
if (rpe <= 4) return 0.5 + (rpe-4)*0.05; // Lower end RPEs are harder to model
// Crude interpolation/lookup
var rpeMap = {
10: {1: 1.00, 2: 0.93, 3: 0.87, 4: 0.83, 5: 0.80, 6: 0.77, 7: 0.74, 8: 0.71, 9: 0.69, 10: 0.67},
9: {1: 0.90, 2: 0.85, 3: 0.80, 4: 0.76, 5: 0.73, 6: 0.70, 7: 0.67, 8: 0.64, 9: 0.62, 10: 0.60},
8: {1: 0.80, 2: 0.77, 3: 0.73, 4: 0.69, 5: 0.66, 6: 0.63, 7: 0.60, 8: 0.57, 9: 0.55, 10: 0.53},
7: {1: 0.70, 2: 0.68, 3: 0.65, 4: 0.61, 5: 0.58, 6: 0.55, 7: 0.52, 8: 0.49, 9: 0.47, 10: 0.45},
6: {1: 0.60, 2: 0.55, 3: 0.50, 4: 0.47, 5: 0.44, 6: 0.41, 7: 0.38, 8: 0.35, 9: 0.33, 10: 0.31},
5: {1: 0.50, 2: 0.45, 3: 0.40, 4: 0.37, 5: 0.34, 6: 0.31, 7: 0.28, 8: 0.25, 9: 0.23, 10: 0.21}
};
if (rpeMap[rpe] && rpeMap[rpe][reps]) {
return rpeMap[rpe][reps];
}
// Fallback for reps outside the table
if (reps 10) { // Extrapolate for higher reps
var baseReps = 10;
var basePerc = rpeMap[rpe][baseReps] || 0.21; // RPE 5 for 10 reps is 0.21
var multiplier = Math.pow(baseReps / reps, 0.1); // Crude extrapolation factor
return basePerc * multiplier;
}
// Crude linear interpolation for reps within range if not exact match
var lowerReps = Math.floor(reps);
var upperReps = Math.ceil(reps);
if (lowerReps > 0 && upperReps 0) {
var effectivePerc = estimatedWeightForTargetReps / estimated1RM_final;
// Find the RPE that corresponds to 'effectivePerc' for 'targetReps'
// This is also complex. Let's use the initial RPE lookup table and find the closest RPE.
// For simplicity, assume the calculated weight *should* hit target RPE if model is perfect.
// We'll display the target RPE as the "estimated" RPE for confirmation.
calculatedRPE = targetRPE; // Simplification: assume the target is hit.
}
// Display results
document.getElementById("mainResult").innerText = formatWeight(estimatedWeightForTargetReps) + " (" + getWeightUnit() + ")";
document.getElementById("estimated1RM").innerText = "Estimated 1RM: " + formatWeight(estimated1RM_final) + " (" + getWeightUnit() + ")";
document.getElementById("estimatedWeightForTargetReps").innerText = "Estimated Weight for Target Reps: " + formatWeight(estimatedWeightForTargetReps) + " (" + getWeightUnit() + ")";
document.getElementById("estimatedRPEAtTargetWeight").innerText = "Estimated RPE at Target Weight: " + calculatedRPE.toFixed(1);
updateChart(estimated1RM_final, targetRPE, targetReps);
}
function formatWeight(weight) {
if (isNaN(weight) || weight === Infinity || weight === -Infinity) return "–";
return weight.toFixed(2); // Default to 2 decimal places
}
function getWeightUnit() {
// This calculator doesn't specify units, so it's implied by user input.
// We can add a unit selector later. For now, assume consistency.
return "kg/lbs"; // Placeholder
}
function resetCalculator() {
document.getElementById("targetRPE").value = 8;
document.getElementById("knownRPE").value = 10;
document.getElementById("knownWeight").value = 100;
document.getElementById("targetReps").value = 5;
document.getElementById("knownReps").value = 1;
// Clear results
document.getElementById("mainResult").innerText = "–";
document.getElementById("estimated1RM").innerText = "Estimated 1RM: –";
document.getElementById("estimatedWeightForTargetReps").innerText = "Estimated Weight for Target Reps: –";
document.getElementById("estimatedRPEAtTargetWeight").innerText = "Estimated RPE at Target Weight: –";
// Clear errors
document.getElementById("targetRPEError").innerText = "";
document.getElementById("knownRPEError").innerText = "";
document.getElementById("knownWeightError").innerText = "";
document.getElementById("targetRepsError").innerText = "";
document.getElementById("knownRepsError").innerText = "";
// Clear chart
if (chartInstance) {
chartInstance.destroy();
chartInstance = null;
}
var ctx = document.getElementById("rpeChart").getContext("2d");
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
}
function copyResults() {
var mainResult = document.getElementById("mainResult").innerText;
var estimated1RM = document.getElementById("estimated1RM").innerText;
var estimatedWeight = document.getElementById("estimatedWeightForTargetReps").innerText;
var estimatedRPE = document.getElementById("estimatedRPEAtTargetWeight").innerText;
var resultsText = "RPE Weight Calculator Results:\n";
resultsText += "—————————–\n";
resultsText += "Primary Result (Weight for Target Reps): " + mainResult + "\n";
resultsText += estimated1RM + "\n";
resultsText += estimatedWeight + "\n";
resultsText += estimatedRPE + "\n";
resultsText += "\nKey Assumptions:\n";
resultsText += "- RPE scale is accurately perceived.\n";
resultsText += "- Strength performance follows predictable models.\n";
resultsText += "- Consistent training tempo and range of motion.\n";
try {
navigator.clipboard.writeText(resultsText).then(function() {
// Success feedback (optional)
var btn = document.getElementById('copyResultsBtn');
btn.innerText = 'Copied!';
setTimeout(function() { btn.innerText = 'Copy Results'; }, 2000);
}, function(err) {
console.error('Could not copy text: ', err);
var btn = document.getElementById('copyResultsBtn');
btn.innerText = 'Copy Failed';
setTimeout(function() { btn.innerText = 'Copy Results'; }, 2000);
});
} catch (e) {
console.error("Clipboard API not available", e);
// Fallback for older browsers (requires user interaction or specific permissions)
alert("Copy to clipboard failed. Please manually copy the results.");
}
}
// Charting Logic
function updateChart(estimated1RM, targetRPE, targetReps) {
var ctx = document.getElementById("rpeChart").getContext("2d");
// Clear previous chart if it exists
if (chartInstance) {
chartInstance.destroy();
}
// Generate data points for the chart
var repsData = [];
var rpeData10 = []; // For RPE 10 (1RM)
var rpeDataTarget = []; // For the target RPE
// Helper function to get RPE % from RPE and Reps (using the same logic as calculation)
function getRPEPercentageForChart(rpe, reps) {
if (reps = 10) return 1.0;
if (rpe <= 4) return 0.5 + (rpe-4)*0.05;
var rpeMap = {
10: {1: 1.00, 2: 0.93, 3: 0.87, 4: 0.83, 5: 0.80, 6: 0.77, 7: 0.74, 8: 0.71, 9: 0.69, 10: 0.67},
9: {1: 0.90, 2: 0.85, 3: 0.80, 4: 0.76, 5: 0.73, 6: 0.70, 7: 0.67, 8: 0.64, 9: 0.62, 10: 0.60},
8: {1: 0.80, 2: 0.77, 3: 0.73, 4: 0.69, 5: 0.66, 6: 0.63, 7: 0.60, 8: 0.57, 9: 0.55, 10: 0.53},
7: {1: 0.70, 2: 0.68, 3: 0.65, 4: 0.61, 5: 0.58, 6: 0.55, 7: 0.52, 8: 0.49, 9: 0.47, 10: 0.45},
6: {1: 0.60, 2: 0.55, 3: 0.50, 4: 0.47, 5: 0.44, 6: 0.41, 7: 0.38, 8: 0.35, 9: 0.33, 10: 0.31},
5: {1: 0.50, 2: 0.45, 3: 0.40, 4: 0.37, 5: 0.34, 6: 0.31, 7: 0.28, 8: 0.25, 9: 0.23, 10: 0.21}
};
if (rpeMap[rpe] && rpeMap[rpe][reps]) {
return rpeMap[rpe][reps];
}
if (reps 10) {
var baseReps = 10;
var basePerc = rpeMap[rpe][baseReps] || 0.21;
var multiplier = Math.pow(baseReps / reps, 0.1);
return basePerc * multiplier;
}
var lowerReps = Math.floor(reps);
var upperReps = Math.ceil(reps);
if (lowerReps > 0 && upperReps <= 10 && rpeMap[rpe][lowerReps] && rpeMap[rpe][upperReps]) {
var factor = (reps – lowerReps) / (upperReps – lowerReps);
return rpeMap[rpe][lowerReps] * (1 – factor) + rpeMap[rpe][upperReps] * factor;
}
return 0.5;
}
// Generate data for 1 to 10 reps
for (var r = 1; r <= 10; r++) {
repsData.push(r);
rpeData10.push(estimated1RM * getRPEPercentageForChart(10, r)); // Weight at RPE 10 for 'r' reps
rpeDataTarget.push(estimated1RM * getRPEPercentageForChart(targetRPE, r)); // Weight at Target RPE for 'r' reps
}
// Ensure estimated 1RM is displayed correctly if it's zero or NaN
if (isNaN(estimated1RM) || estimated1RM <= 0) {
estimated1RM = 100; // Default to a reasonable value if calculation failed
}
// Add the specific target point
var targetPointWeight = parseFloat(document.getElementById("mainResult").innerText);
if (isNaN(targetPointWeight) || targetPointWeight <= 0) targetPointWeight = estimated1RM * getRPEPercentageForChart(targetRPE, targetReps);
chartInstance = new Chart(ctx, {
type: 'line',
data: {
labels: repsData, // X-axis: Repetitions
datasets: [
{
label: 'Weight at RPE 10 (Estimated 1RM)',
data: rpeData10, // Y-axis: Weight
borderColor: 'rgba(0, 74, 153, 1)', // Primary color
backgroundColor: 'rgba(0, 74, 153, 0.1)',
fill: false,
tension: 0.1,
pointRadius: 4,
pointHoverRadius: 6
},
{
label: 'Weight at Target RPE (' + targetRPE + ')',
data: rpeDataTarget,
borderColor: 'rgba(40, 167, 69, 1)', // Success color
backgroundColor: 'rgba(40, 167, 69, 0.1)',
fill: false,
tension: 0.1,
pointRadius: 4,
pointHoverRadius: 6
}
]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
x: {
title: {
display: true,
text: 'Repetitions'
}
},
y: {
title: {
display: true,
text: 'Estimated Weight (' + getWeightUnit() + ')'
},
beginAtZero: true
}
},
plugins: {
tooltip: {
callbacks: {
label: function(context) {
var label = context.dataset.label || '';
if (label) {
label += ': ';
}
if (context.parsed.y !== null) {
label += context.parsed.y.toFixed(2) + ' ' + getWeightUnit();
}
return label;
}
}
},
legend: {
position: 'top',
}
}
}
});
}
// Function to toggle FAQ answers
function toggleFaq(element) {
var p = element.nextElementSibling;
if (p.style.display === "block") {
p.style.display = "none";
} else {
p.style.display = "block";
}
}
// Initial calculation on load if inputs have default values
document.addEventListener('DOMContentLoaded', function() {
calculateRPEWeight();
// Add event listeners for input changes to update chart dynamically (optional but good UX)
var inputs = document.querySelectorAll('.loan-calc-container input, .loan-calc-container select');
inputs.forEach(function(input) {
input.addEventListener('input', calculateRPEWeight);
});
});
// Mocking behavior for internal links if they were real anchors
document.addEventListener('DOMContentLoaded', function() {
var internalLinks = document.querySelectorAll('.internal-links a');
internalLinks.forEach(function(link) {
link.addEventListener('click', function(event) {
// Prevent default anchor behavior if needed, or just var it scroll
// event.preventDefault();
// Simulate navigation or scroll to specific section
console.log("Internal link clicked:", link.getAttribute('href'));
});
});
});