Calculating Weight from Bmi and Height

Calculate Your Weight from BMI and Height – BMI Weight Calculator :root { –primary-color: #004a99; –success-color: #28a745; –background-color: #f8f9fa; –text-color: #333; –light-gray: #e9ecef; –white: #fff; } body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: var(–background-color); color: var(–text-color); line-height: 1.6; margin: 0; padding: 0; } .container { max-width: 1000px; margin: 20px auto; padding: 20px; background-color: var(–white); border-radius: 8px; box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1); } h1, h2, h3 { color: var(–primary-color); text-align: center; } h1 { margin-bottom: 15px; } h2 { margin-top: 30px; margin-bottom: 20px; border-bottom: 2px solid var(–light-gray); padding-bottom: 10px; } .calculator-section { background-color: var(–white); padding: 30px; border-radius: 8px; margin-bottom: 30px; box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05); } .loan-calc-container { display: flex; flex-wrap: wrap; gap: 20px; } .input-group { flex: 1 1 250px; 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Calculate Your Target Weight from BMI and Height

Easily determine the weight needed to achieve a specific Body Mass Index (BMI) based on your height.

BMI Weight Calculator

Enter your height in centimeters (e.g., 175 for 1.75m)
Enter your desired BMI value (e.g., 18.5 to 24.9 for a healthy range)

Your Target Weight

Height: — m | Weight: — kg | Height Squared: — m²

Formula: Target Weight (kg) = Target BMI × (Height in meters)²

BMI and Target Weight Data

Chart showing how target weight changes with height for a selected BMI.

Height Range (cm) Calculated Target Weight (kg) for BMI 22.5 Corresponding BMI Category
Loading data…

What is Calculating Weight from BMI and Height?

Calculating your weight from BMI and height is a fundamental concept in understanding body composition and achieving a healthy weight range. It involves using your height and a desired Body Mass Index (BMI) value to determine what your weight should be. BMI is a widely used screening tool that provides a general indication of whether your weight is healthy for your height. By inputting your height and a target BMI, this calculator helps you establish a specific weight goal.

Who should use it? This calculator is beneficial for individuals who are:

  • Looking to understand what weight they should aim for within a specific BMI category (e.g., healthy weight, overweight).
  • Tracking their weight loss or gain journey and want to set realistic, BMI-informed targets.
  • Curious about the relationship between their height, weight, and BMI.
  • Seeking to educate themselves about healthy weight management.

Common misconceptions:

  • BMI is a diagnostic tool: BMI is a screening tool, not a diagnostic measure for body fatness or health. It doesn't account for muscle mass, bone density, or fat distribution.
  • One-size-fits-all BMI: The standard BMI ranges are based on populations and may not be perfectly accurate for all individuals, such as very muscular athletes or the elderly.
  • Lower BMI is always better: While a healthy BMI range is recommended, extremely low BMIs can also indicate health risks.
Our tool focuses on the mathematical relationship to provide a weight target based on a chosen BMI.

BMI Weight Calculation Formula and Mathematical Explanation

The process of calculating your target weight from BMI and height is derived directly from the BMI formula itself. The standard formula for BMI is:

BMI = Weight (kg) / [Height (m)]²

To find the target weight, we rearrange this formula to solve for Weight (kg).

Step 1: Convert Height to Meters Your height is typically measured in centimeters. To use it in the BMI formula, you must convert it to meters by dividing by 100. Height (m) = Height (cm) / 100

Step 2: Square Your Height in Meters Next, you square the height value in meters. Height Squared (m²) = [Height (m)]²

Step 3: Rearrange the BMI Formula Starting with BMI = Weight (kg) / Height Squared (m²), we multiply both sides by Height Squared (m²) to isolate Weight (kg): Weight (kg) = BMI × Height Squared (m²)

This rearranged formula is what our calculator uses. You input your height (in cm) and a desired BMI, and it performs these steps to give you the target weight in kilograms.

Variables Explained

Variable Meaning Unit Typical Range
Height The vertical distance from the sole of a person's foot to the top of their head. Centimeters (cm) or Meters (m) 140 – 200 cm (approx.)
Target BMI The desired Body Mass Index value, indicating a weight goal. kg/m² 18.5 – 24.9 (Healthy), 25 – 29.9 (Overweight), ≥30 (Obese)
Calculated Weight The weight in kilograms needed to achieve the Target BMI for the given height. Kilograms (kg) Varies based on height and BMI
Height Squared The height in meters multiplied by itself. Varies based on height

Practical Examples (Real-World Use Cases)

Example 1: Setting a Healthy Weight Goal

Sarah is 165 cm tall and wants to know what her weight should be to fall within the 'healthy' BMI range, specifically aiming for a BMI of 21.

  • Inputs: Height = 165 cm, Target BMI = 21
  • Calculation:
    • Height in meters = 165 / 100 = 1.65 m
    • Height squared = 1.65 m * 1.65 m = 2.7225 m²
    • Target Weight = 21 kg/m² * 2.7225 m² = 57.17 kg
  • Result: Sarah's target weight for a BMI of 21 is approximately 57.2 kg.
  • Interpretation: This gives Sarah a clear, measurable goal for her weight management efforts. It's a weight that aligns with established healthy BMI guidelines for her height.

Example 2: Understanding Weight for a Taller Individual

John is 190 cm tall and wants to know the weight that corresponds to a BMI of 24 (at the upper end of the healthy range).

  • Inputs: Height = 190 cm, Target BMI = 24
  • Calculation:
    • Height in meters = 190 / 100 = 1.90 m
    • Height squared = 1.90 m * 1.90 m = 3.61 m²
    • Target Weight = 24 kg/m² * 3.61 m² = 86.64 kg
  • Result: John's target weight for a BMI of 24 is approximately 86.6 kg.
  • Interpretation: For a taller individual like John, the weight associated with a healthy BMI is naturally higher than for someone of shorter stature. This calculation helps clarify that his goal weight is appropriate for his height and within healthy parameters.

How to Use This BMI Weight Calculator

Our BMI Weight Calculator is designed for simplicity and ease of use. Follow these steps to find your target weight:

  1. Enter Your Height: In the "Height" field, input your height accurately in centimeters (e.g., if you are 1 meter and 75 centimeters tall, enter 175). Ensure this value is a positive number.
  2. Set Your Target BMI: In the "Target BMI" field, enter the specific BMI value you wish to achieve. Common healthy BMIs range from 18.5 to 24.9. You can choose a specific number within this range or even explore BMIs associated with overweight or underweight categories if needed for context.
  3. View Instant Results: As soon as you enter valid numbers, the calculator will instantly update.
    • Main Result (Calculated Weight): This prominently displayed number shows the target weight in kilograms required to meet your specified BMI for your height.
    • Intermediate Values: You'll see your height converted to meters, the squared value of your height in meters, and the formula used, providing transparency.
  4. Understand the Formula: A clear explanation of the formula (Target Weight = Target BMI × Height²) is provided.
  5. Analyze the Chart and Table: The dynamic chart visualizes how weight changes with height for a fixed BMI, and the table offers a quick reference for target weights across different height ranges.
  6. Reset or Copy: Use the "Reset" button to clear current inputs and return to default values. The "Copy Results" button allows you to easily share or save the main result and intermediate values.

Decision-Making Guidance: Use the calculated target weight as a guide. Consult with healthcare professionals to ensure your weight goals are appropriate for your individual health status, considering factors beyond BMI such as body composition, fitness level, and medical history. This tool provides a mathematical target, not medical advice.

Key Factors That Affect BMI and Target Weight Calculations

While the calculation for target weight from BMI and height is straightforward, several factors influence what a "healthy" or "ideal" weight truly means for an individual. Understanding these nuances is crucial for effective weight management.

  • Body Composition (Muscle vs. Fat): BMI does not differentiate between muscle mass and fat mass. A very muscular person might have a high BMI but a low body fat percentage, indicating they are healthy. Conversely, someone with a "healthy" BMI might have a high body fat percentage and low muscle mass, which carries health risks. Therefore, the calculated target weight might be too low for highly muscular individuals or potentially misleading for those with sarcopenia (age-related muscle loss).
  • Age: As people age, body composition naturally changes. Muscle mass tends to decrease, and body fat may increase. This can affect how BMI relates to health. Recommended BMI ranges and target weights might need consideration for older adults, where a slightly higher BMI could sometimes be associated with better health outcomes than a very low one.
  • Sex/Gender: Biological differences between males and females can influence body composition, with men typically having more muscle mass and women having a higher essential body fat percentage. While the BMI formula itself is gender-neutral, its interpretation in terms of health risks and ideal body fat percentages can differ.
  • Genetics: Genetic predispositions play a role in metabolism, fat storage, and body frame. Some individuals may find it easier to maintain a certain weight or body composition than others, regardless of diet and exercise. This means a calculated target weight might be more challenging to achieve or maintain for some due to their genetic makeup.
  • Bone Density and Frame Size: Individuals with a larger bone structure or higher bone density will naturally weigh more than those with a smaller frame, even if they have similar body fat percentages. BMI does not account for frame size, so the calculated target weight might not be suitable for individuals with naturally larger frames.
  • Health Conditions and Medications: Certain medical conditions (like thyroid disorders, PCOS) and medications can significantly impact weight, metabolism, and body composition. These factors can make achieving or maintaining a specific weight target more complex and require personalized medical guidance rather than relying solely on BMI calculations.
  • Activity Level and Fitness: A highly active individual, especially one engaged in strength training, will have more muscle mass. This will increase their weight for a given height compared to a sedentary person. The calculated target weight might seem low if the goal is to maintain significant muscle mass.

Frequently Asked Questions (FAQ)

What is the ideal BMI range?

The generally accepted "healthy" BMI range for adults is 18.5 to 24.9. BMIs below 18.5 are considered underweight, 25.0 to 29.9 are overweight, and 30.0 or higher are obese. However, these are guidelines and may not apply perfectly to everyone.

Can I use this calculator if my height is in feet and inches?

Yes, but you need to convert your height to centimeters first. For example, 5 feet 9 inches is approximately 175 cm (5 feet * 12 inches/foot + 9 inches = 69 inches; 69 inches * 2.54 cm/inch ≈ 175 cm). Enter the total centimeters into the calculator.

Does the calculator account for muscle mass?

No, the calculator uses the standard BMI formula, which does not distinguish between muscle mass and fat mass. A very muscular individual might have a higher weight than calculated for a "healthy" BMI. Always consider body composition alongside BMI.

What does it mean if my calculated target weight is very low or very high?

It means that for your height, achieving the specific BMI you entered would result in a weight at that end of the spectrum. For very low calculated weights, it might indicate an underweight BMI category, while very high weights suggest an overweight or obese category. Always assess if these targets are realistic and healthy for you, consulting a professional if unsure.

How often should I recalculate my target weight?

You generally don't need to recalculate your target weight frequently unless your height changes (which is rare after adolescence) or if you decide to aim for a different BMI category. Your height is a constant, and your target BMI is a personal goal. Focus on monitoring your actual weight and consulting with healthcare providers.

Is BMI the best measure of health?

BMI is a useful starting point and screening tool but is not the sole or definitive measure of health. Factors like body fat percentage, waist circumference, fitness levels, diet, blood pressure, cholesterol levels, and overall lifestyle are also critical indicators of health.

Can children use this calculator?

This calculator is designed for adults. BMI interpretation for children and adolescents differs significantly due to ongoing growth and development, using age and sex-specific growth charts. It's best to consult a pediatrician for BMI information related to children.

What if I want to calculate BMI from weight and height?

This calculator works in reverse, calculating weight from BMI and height. If you have your weight and height and want to calculate your current BMI, you would use the standard formula: BMI = Weight (kg) / [Height (m)]². Many dedicated BMI calculators can perform this for you.

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function calculateBmiWeight() { var heightCmInput = document.getElementById("heightCm"); var targetBmiInput = document.getElementById("targetBmi"); var heightCmError = document.getElementById("heightCmError"); var targetBmiError = document.getElementById("targetBmiError"); var calculatedWeightDiv = document.getElementById("calculatedWeight"); var heightMetersSpan = document.getElementById("heightMeters"); var bmiFormulaWeightSpan = document.getElementById("bmiFormulaWeight"); var bmiFormulaHeightSquaredSpan = document.getElementById("bmiFormulaHeightSquared"); var heightCm = parseFloat(heightCmInput.value); var targetBmi = parseFloat(targetBmiInput.value); // Reset errors heightCmError.innerText = ""; heightCmError.classList.remove("visible"); targetBmiError.innerText = ""; targetBmiError.classList.remove("visible"); var isValid = true; if (isNaN(heightCm) || heightCm 300) { // Practical upper limit for human height heightCmError.innerText = "Height seems too large. Please enter a realistic value."; heightCmError.classList.add("visible"); isValid = false; } if (isNaN(targetBmi) || targetBmi <= 0) { targetBmiError.innerText = "Please enter a valid BMI value (must be positive)."; targetBmiError.classList.add("visible"); isValid = false; } else if (targetBmi 100) { // Realistic BMI range check targetBmiError.innerText = "BMI value is outside a typical realistic range."; targetBmiError.classList.add("visible"); isValid = false; } if (!isValid) { calculatedWeightDiv.innerText = "–"; heightMetersSpan.innerText = "Height: — m"; bmiFormulaWeightSpan.innerText = "Weight: — kg"; bmiFormulaHeightSquaredSpan.innerText = "Height Squared: — m²"; updateChartAndTable(); // Clear chart/table on invalid input return; } var heightMeters = heightCm / 100; var heightSquared = Math.pow(heightMeters, 2); var calculatedWeight = targetBmi * heightSquared; calculatedWeightDiv.innerText = calculatedWeight.toFixed(1); heightMetersSpan.innerText = "Height: " + heightMeters.toFixed(2) + " m"; bmiFormulaWeightSpan.innerText = "Weight: " + calculatedWeight.toFixed(1) + " kg"; bmiFormulaHeightSquaredSpan.innerText = "Height Squared: " + heightSquared.toFixed(4) + " m²"; updateChartAndTable(heightMeters, calculatedWeight); } function resetCalculator() { document.getElementById("heightCm").value = "175"; document.getElementById("targetBmi").value = "22.5"; calculateBmiWeight(); } function copyResults() { var mainResult = document.getElementById("calculatedWeight").innerText; var heightMeterText = document.getElementById("heightMeters").innerText; var bmiWeightText = document.getElementById("bmiFormulaWeight").innerText; var bmiHeightSquaredText = document.getElementById("bmiFormulaHeightSquared").innerText; var formula = document.querySelector(".formula-explanation").innerText; var textToCopy = "Your Target Weight Calculation:\n\n"; textToCopy += "Result: " + mainResult + " kg\n"; textToCopy += heightMeterText + "\n"; textToCopy += bmiWeightText + "\n"; textToCopy += bmiHeightSquaredText + "\n\n"; textToCopy += "Formula: " + formula; var textArea = document.createElement("textarea"); textArea.value = textToCopy; textArea.style.position = "fixed"; textArea.style.left = "-9999px"; document.body.appendChild(textArea); textArea.focus(); textArea.select(); try { var successful = document.execCommand('copy'); var msg = successful ? 'Results copied!' : 'Failed to copy results.'; console.log(msg); // Optionally show a temporary message to the user var copyButton = document.querySelector(".btn-success[onclick='copyResults()']"); var originalText = copyButton.innerText; copyButton.innerText = "Copied!"; setTimeout(function() { copyButton.innerText = originalText; }, 2000); } catch (err) { console.error('Fallback: Oops, unable to copy', err); } document.body.removeChild(textArea); } function updateChartAndTable(currentHeightMeters = null, currentTargetWeight = null) { var ctx = document.getElementById('bmiChart').getContext('2d'); var targetBmiValue = parseFloat(document.getElementById("targetBmi").value); var heightCmValue = parseFloat(document.getElementById("heightCm").value); // Clear previous chart if (window.bmiChartInstance) { window.bmiChartInstance.destroy(); } var heightsCm = [150, 160, 170, 180, 190, 200]; // Example heights var bmiCategories = { "Underweight": { min: 0, max: 18.4, color: '#6c757d' }, "Healthy Weight": { min: 18.5, max: 24.9, color: 'var(–success-color)' }, "Overweight": { min: 25, max: 29.9, color: '#ffc107' }, "Obese": { min: 30, max: Infinity, color: '#dc3545' } }; var chartDataSets = []; var allWeights = []; // To determine chart y-axis limits // Data series for selected BMI var selectedBmiWeights = []; var chartLabels = heightsCm.map(function(hCm) { var hM = hCm / 100; var hSquared = Math.pow(hM, 2); var weight = targetBmiValue * hSquared; selectedBmiWeights.push(weight); allWeights.push(weight); return hCm + " cm"; }); chartDataSets.push({ label: 'Target Weight (for BMI ' + targetBmiValue.toFixed(1) + ')', data: selectedBmiWeights, borderColor: 'var(–primary-color)', backgroundColor: 'rgba(0, 74, 153, 0.2)', fill: false, tension: 0.1 }); // Optional: Add a series for a different BMI (e.g., healthy average BMI) var avgHealthyBmi = 22.5; var avgHealthyWeights = []; heightsCm.forEach(function(hCm) { var hM = hCm / 100; var hSquared = Math.pow(hM, 2); var weight = avgHealthyBmi * hSquared; avgHealthyWeights.push(weight); allWeights.push(weight); }); chartDataSets.push({ label: 'Weight for Avg Healthy BMI (' + avgHealthyBmi.toFixed(1) + ')', data: avgHealthyWeights, borderColor: 'var(–success-color)', backgroundColor: 'rgba(40, 167, 69, 0.2)', fill: false, tension: 0.1 }); var maxY = Math.max(…allWeights) * 1.15; // Add some padding var minY = Math.min(…allWeights) * 0.85; if (minY = bmiCategories[category].min * Math.pow(hM, 2) && weightForTargetBmi <= bmiCategories[category].max * Math.pow(hM, 2)) { correspondingCategory = category; break; } } var row = tableBody.insertRow(); var cellHeight = row.insertCell(0); var cellWeight = row.insertCell(1); var cellCategory = row.insertCell(2); cellHeight.innerHTML = hCm + " cm"; cellWeight.innerHTML = weightForTargetBmi.toFixed(1) + " kg"; cellCategory.innerHTML = correspondingCategory; }); } function toggleFaq(element) { var faqItem = element.parentElement; faqItem.classList.toggle('open'); } // Initial calculation and chart rendering on page load document.addEventListener("DOMContentLoaded", function() { // Add event listeners to inputs for real-time updates document.getElementById("heightCm").addEventListener("input", calculateBmiWeight); document.getElementById("targetBmi").addEventListener("input", calculateBmiWeight); calculateBmiWeight(); // Perform initial calculation // Ensure Chart.js is loaded before trying to use it if (typeof Chart !== 'undefined') { updateChartAndTable(); } else { console.error("Chart.js not loaded. Please ensure it's included."); // Optionally load Chart.js dynamically or provide a fallback var script = document.createElement('script'); script.src = 'https://cdn.jsdelivr.net/npm/chart.js'; script.onload = function() { updateChartAndTable(); }; document.head.appendChild(script); } });

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