Hitch Weight Calculator

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Hitch Weight Calculator

Ensure safe towing by accurately calculating your RV's hitch weight and tongue weight percentage.

Total weight the trailer is designed to carry (lbs).
Weight on the trailer hitch (lbs).
Maximum tongue weight your tow vehicle can handle (lbs).
Maximum trailer weight your tow vehicle can tow (lbs).
— %

Tongue Weight Percentage

— lbs Actual Tongue Weight
— % Calculated Percentage
Towing Limits
Tongue Weight Percentage = (Trailer Tongue Weight / Trailer Gross Vehicle Weight Rating) * 100%
Towing Capacity Summary
Metric Value Status/Recommendation
Actual Tongue Weight — lbs
Calculated Tongue Weight % — %
Tow Vehicle Max Tongue Weight — lbs
Tow Vehicle Max Trailer Weight — lbs
Comparison of Trailer Weight vs. Tow Vehicle Capacities

What is Hitch Weight?

Hitch weight, often referred to as tongue weight in the context of travel trailers and fifth wheels, is the downward force that the trailer exerts on the hitch ball or kingpin of the tow vehicle. It is a critical measurement for ensuring safe and stable towing. Understanding your hitch weight is crucial because it directly impacts how your vehicle handles, its stability, and the overall safety of your towing setup. For travel trailers, the tongue weight is typically estimated to be between 10-15% of the trailer's total loaded weight. For fifth wheels, this percentage is often higher, ranging from 15-25%. This distribution is vital; too little hitch weight can lead to trailer sway and loss of control, while excessive hitch weight can overload the tow vehicle's suspension and chassis, potentially leading to steering and braking issues.

Who Should Use a Hitch Weight Calculator?

Anyone planning to tow a recreational vehicle (RV), such as a travel trailer, fifth wheel, or even some smaller utility trailers, should understand and ideally calculate their hitch weight. This includes:

  • New RV owners trying to understand the specifications of their trailer and tow vehicle.
  • Those who have recently purchased a new trailer or tow vehicle and want to confirm compatibility.
  • Campers who frequently change their trailer's loadout (e.g., adding water, changing gear) and want to monitor how it affects tongue weight.
  • Individuals experiencing towing instability or concerns about their setup's safety.

Common Misconceptions about Hitch Weight

  • "Hitch weight is the same as trailer weight." This is incorrect. Hitch weight is only a portion of the trailer's total weight, specifically the portion pressing down on the tow vehicle's hitch.
  • "Any vehicle can tow any trailer if properly hitched." Vehicle towing capacities and tongue weight limits are strict engineering specifications that must not be exceeded for safety.
  • "Tongue weight percentage is flexible." While there's a range (e.g., 10-15% for travel trailers), significantly deviating from the recommended range can compromise stability.

Hitch Weight Calculator Formula and Mathematical Explanation

The core calculation for determining the safety and suitability of a towing setup revolves around the tongue weight percentage and comparing it against vehicle and trailer limits. Our hitch weight calculator utilizes these fundamental principles.

The Primary Formula: Tongue Weight Percentage

The most common and crucial metric derived from hitch weight is the tongue weight percentage. This tells you how much of the trailer's total weight is bearing down on the hitch.

Tongue Weight Percentage = (Trailer Tongue Weight / Trailer Gross Vehicle Weight Rating) * 100%

Explanation of Variables:

  • Trailer Tongue Weight: This is the actual measured or estimated weight that the trailer imposes directly on the tow vehicle's hitch (e.g., trailer ball or fifth-wheel pin). This is the weight you are measuring at the hitch point.
  • Trailer Gross Vehicle Weight Rating (GVWR): This is the maximum weight that the trailer is designed to safely carry, including its own weight when fully loaded with cargo, water, propane, etc. It's the manufacturer's specified maximum for the trailer.

Towing Limit Checks

Beyond the percentage, the calculator also checks against the tow vehicle's rated capacities:

  • Tow Vehicle Max Tongue Weight: The maximum downward force the tow vehicle's hitch receiver and chassis are designed to handle.
  • Tow Vehicle Max Trailer Weight: The maximum weight of the trailer the tow vehicle is engineered to tow.
Hitch Weight Calculator Variables
Variable Meaning Unit Typical Range / Recommendation
Trailer Tongue Weight Downward force exerted by the trailer on the hitch. lbs Actual measured or estimated value.
Trailer GVWR Maximum loaded weight the trailer is designed to carry. lbs Manufacturer's specification. Crucial for percentage calculation.
Tongue Weight Percentage Ratio of tongue weight to trailer GVWR, indicating load balance. % 10-15% for travel trailers; 15-25% for fifth wheels. Critical for stability.
Tow Vehicle Max Tongue Weight Maximum downward force the tow vehicle hitch can safely support. lbs Manufacturer's specification. Must not be exceeded.
Tow Vehicle Max Trailer Weight Maximum weight the tow vehicle can safely tow. lbs Manufacturer's specification. Must not be exceeded.

Practical Examples (Real-World Use Cases)

Example 1: Travel Trailer Setup

Sarah is planning a cross-country trip with her new travel trailer. She wants to ensure her setup is safe.

  • Trailer Gross Vehicle Weight Rating (GVWR): 7,500 lbs
  • Actual Trailer Tongue Weight (measured): 950 lbs
  • Tow Vehicle Max Tongue Weight: 1,000 lbs
  • Tow Vehicle Max Trailer Weight: 10,000 lbs

Calculation:

  • Actual Tongue Weight: 950 lbs
  • Tongue Weight Percentage: (950 lbs / 7,500 lbs) * 100% = 12.67%
  • Tow Vehicle Max Tongue Weight Check: 950 lbs is less than 1,000 lbs (OK)
  • Tow Vehicle Max Trailer Weight Check: Assuming the trailer is currently loaded near its GVWR of 7,500 lbs, this is well below the vehicle's 10,000 lbs limit (OK).

Interpretation:

Sarah's setup is within safe limits. The tongue weight percentage of 12.67% falls nicely within the recommended 10-15% range for travel trailers, indicating good stability. Her actual tongue weight is also below the vehicle's maximum capacity.

Example 2: Potential Overload Scenario

Mark is loading his toy hauler before a trip. He's concerned about exceeding limits.

  • Trailer Gross Vehicle Weight Rating (GVWR): 12,000 lbs
  • Actual Trailer Tongue Weight (estimated): 1,800 lbs (loaded with toys)
  • Tow Vehicle Max Tongue Weight: 1,500 lbs
  • Tow Vehicle Max Trailer Weight: 14,000 lbs

Calculation:

  • Actual Tongue Weight: 1,800 lbs
  • Tongue Weight Percentage: (1,800 lbs / 12,000 lbs) * 100% = 15%
  • Tow Vehicle Max Tongue Weight Check: 1,800 lbs is GREATER than 1,500 lbs (NOT OK)
  • Tow Vehicle Max Trailer Weight Check: If the trailer is at its 12,000 lbs GVWR, it's below the vehicle's 14,000 lbs limit (OK).

Interpretation:

Although Mark's tongue weight percentage (15%) is at the higher end of the acceptable range for some trailers, the critical issue is that his actual tongue weight (1,800 lbs) exceeds his tow vehicle's maximum rated tongue weight (1,500 lbs). This situation poses a significant safety risk. Mark needs to redistribute the cargo in his trailer, shifting weight towards the rear, or reduce the amount of cargo to lower the tongue weight to a safe level before towing. Relying solely on the hitch weight calculator helps identify these critical safety issues.

How to Use This Hitch Weight Calculator

Using our hitch weight calculator is straightforward and essential for safe towing. Follow these steps:

  1. Identify Trailer GVWR: Find the Gross Vehicle Weight Rating (GVWR) for your trailer. This is usually found on a sticker or plate on the trailer's frame or doorjamb. It represents the maximum loaded weight.
  2. Determine Actual Tongue Weight: Measure the actual downward force your trailer exerts on the hitch. This can be done using a tongue weight scale available at many RV service centers or truck stops, or by using a Sherline scale. If you don't have a scale, you can estimate it as 10-15% of the trailer's *current loaded weight* for travel trailers, or 15-25% for fifth wheels, but a physical measurement is always best.
  3. Find Tow Vehicle Limits: Locate your tow vehicle's maximum tongue weight rating and maximum trailer weight rating. These are typically found in your vehicle's owner's manual or on a sticker on the driver's side doorjamb or hitch receiver.
  4. Input the Values: Enter these four numbers (Trailer GVWR, Actual Trailer Tongue Weight, Tow Vehicle Max Tongue Weight, Tow Vehicle Max Trailer Weight) into the corresponding fields in the calculator.
  5. Calculate: Click the "Calculate" button.

How to Read the Results:

  • Main Result (Tongue Weight Percentage): This is the most critical indicator of load balance. Ensure it falls within the recommended range for your RV type (typically 10-15% for travel trailers, 15-25% for fifth wheels).
  • Actual Tongue Weight: This confirms the measured weight on your hitch.
  • Calculated Percentage: This is the same as the main result, shown for clarity.
  • Towing Limits Status: This section provides a quick summary of whether your setup is within the tow vehicle's tongue weight and trailer weight capacities.
  • Table Summary: Provides a detailed breakdown comparing your current setup against the vehicle's limits.
  • Chart: Visually represents the comparison between your trailer weight and the tow vehicle's capacities.

Decision-Making Guidance:

If the calculated tongue weight percentage is too low (e.g., below 10% for a travel trailer), it indicates a risk of trailer sway. You should add weight to the tongue by moving cargo forward in the trailer or adding items like heavier water tanks closer to the front. If the percentage is too high (e.g., above 15% for a travel trailer, or exceeding vehicle limits), you risk overloading your tow vehicle's suspension and chassis. Try redistributing cargo towards the rear of the trailer. Always ensure your actual tongue weight and trailer weight do not exceed your tow vehicle's specified limits.

Key Factors That Affect Hitch Weight Results

Several factors can influence your hitch weight calculations and the overall safety of your towing experience. Understanding these is key to maintaining a balanced and secure setup.

  1. Cargo Loading and Distribution: This is the most significant variable. Heavy items like water tanks, generators, or cargo stored towards the rear of the trailer will decrease tongue weight, while items stored towards the front increase it. Improper loading is a primary cause of incorrect hitch weight percentages.
  2. Water and Fluid Levels: Carrying fresh water, grey water, or black water significantly impacts the trailer's total weight and, consequently, its tongue weight. A full 40-gallon fresh water tank adds over 330 lbs! Plan your water usage and consider towing with empty tanks if possible, especially for long distances, to manage weight.
  3. Trailer Type and Design: Different trailer types have inherently different tongue weight characteristics. Travel trailers typically require 10-15% of their loaded weight on the tongue for stability. Fifth wheels, due to their axle placement and hitch design, often require 15-25% and naturally distribute more weight over the truck's rear axle.
  4. Hitch Type and Installation: The type of hitch (e.g., weight-distribution hitch, gooseneck, standard ball hitch) and its correct installation can affect how tongue weight is managed and distributed. A properly functioning weight-distribution hitch can help manage tongue weight and reduce sway.
  5. Tire Pressure and Condition: While not directly affecting the weight calculation, correctly inflated tires on both the trailer and tow vehicle are crucial for handling the imposed loads and maintaining stability, especially when dealing with calculated hitch weights.
  6. Road Conditions and Speed: Unexpected events like hitting a pothole or sudden braking can temporarily shift weight and put stress on the hitch. Maintaining appropriate hitch weight percentages provides a buffer for these dynamic forces and contributes to a more stable ride, reducing the risk of dangerous swaying.
  7. Wear and Tear: Over time, components like suspension and hitch mechanisms can wear, potentially altering weight distribution slightly. Regular inspection and maintenance are advised.

Frequently Asked Questions (FAQ)

Q1: What is the ideal tongue weight percentage for a travel trailer?

A: For most travel trailers, the ideal tongue weight percentage is between 10% and 15% of the trailer's loaded weight (Gross Vehicle Weight). Staying within this range promotes stability and prevents trailer sway.

Q2: What about fifth wheels? Is the percentage different?

A: Yes, fifth wheels typically require a higher tongue weight percentage, usually between 15% and 25% of their loaded weight. This is due to their hitch design and axle placement, which naturally shifts more weight forward.

Q3: My trailer's tongue weight is exactly at my tow vehicle's max rating. Is that okay?

A: While technically within the limit, being right at the maximum rating leaves no room for error or dynamic forces encountered while driving. It's generally safer to be comfortably below the maximum limit (e.g., aim for 80-90% of capacity) to ensure a margin of safety.

Q4: Can I use a weight-distribution hitch to compensate for incorrect tongue weight?

A: A weight-distribution hitch is designed to help distribute the tongue weight more evenly between the trailer axles and the tow vehicle axles, and to help control sway. However, it does not change the *actual* tongue weight itself. You must still ensure your actual tongue weight is within the tow vehicle's limits *before* using a weight-distribution system.

Q5: How do I measure my trailer's tongue weight accurately?

A: The most accurate method is using a dedicated tongue weight scale (like a Sherline scale) placed under the hitch coupler or pin when the trailer is at its normal hitch height. Alternatively, some truck stops or RV service centers offer weighing services.

Q6: What happens if my tongue weight is too low?

A: A tongue weight that is too low (e.g., less than 10% for a travel trailer) can make the trailer highly susceptible to dangerous swaying. This can lead to a loss of control, especially at higher speeds or during sudden maneuvers.

Q7: What happens if my tongue weight is too high?

A: Excessive tongue weight can overload the tow vehicle's rear suspension, potentially damaging it. It can also negatively affect steering, braking, and the overall handling of the tow vehicle, making it feel like the trailer is pushing the truck around.

Q8: Does the calculator account for tongue weight added by weight-distribution hitches?

A: No, this calculator focuses on the *actual* downward force the trailer itself exerts on the hitch. Weight-distribution hitches redistribute this force but do not reduce the fundamental downward pull of the trailer's loaded weight on the hitch point. Always ensure your trailer's inherent tongue weight is manageable for your vehicle.

Related Tools and Internal Resources

© 2023 Your RVing Authority. All rights reserved.

Information provided is for educational purposes. Always consult your vehicle and trailer owner's manuals and a qualified professional for specific towing advice.

var trailerWeightInput = document.getElementById('trailerWeight'); var trailerTongueWeightInput = document.getElementById('trailerTongueWeight'); var towVehicleMaxTongueWeightInput = document.getElementById('towVehicleMaxTongueWeight'); var towVehicleMaxTrailerWeightInput = document.getElementById('towVehicleMaxTrailerWeight'); var mainResultDiv = document.getElementById('main-result'); var actualTongueWeightSpan = document.getElementById('actualTongueWeight'); var calculatedTongueWeightPercentSpan = document.getElementById('calculatedTongueWeightPercent'); var weightLimitStatusDiv = document.getElementById('weightLimitStatus'); var tableTongueWeightCell = document.getElementById('tableTongueWeight'); var tableTonguePercentCell = document.getElementById('tableTonguePercent'); var tableMaxTongueCell = document.getElementById('tableMaxTongue'); var tableMaxTrailerCell = document.getElementById('tableMaxTrailer'); var tableTongueWeightStatusCell = document.getElementById('tableTongueWeightStatus'); var tableTonguePercentStatusCell = document.getElementById('tableTonguePercentStatus'); var tableMaxTongueStatusCell = document.getElementById('tableMaxTongueStatus'); var tableMaxTrailerStatusCell = document.getElementById('tableMaxTrailerStatus'); var trailerWeightError = document.getElementById('trailerWeightError'); var trailerTongueWeightError = document.getElementById('trailerTongueWeightError'); var towVehicleMaxTongueWeightError = document.getElementById('towVehicleMaxTongueWeightError'); var towVehicleMaxTrailerWeightError = document.getElementById('towVehicleMaxTrailerWeightError'); var towingChart; var chartContext = document.getElementById('towingChart').getContext('2d'); function updateChart(calculatedPercent, trailerWeight, towVehicleMaxTrailer, towVehicleMaxTongue) { if (towingChart) { towingChart.destroy(); } var trailerWeightValue = parseFloat(trailerWeight); var towVehicleMaxTrailerValue = parseFloat(towVehicleMaxTrailer); var towVehicleMaxTongueValue = parseFloat(towVehicleMaxTongue); var data = { labels: ['Trailer Weight', 'Tow Vehicle Max Trailer', 'Tow Vehicle Max Tongue Weight'], datasets: [{ label: 'Weight (lbs)', data: [ trailerWeightValue, towVehicleMaxTrailerValue, towVehicleMaxTongueValue ], backgroundColor: [ 'rgba(0, 74, 153, 0.6)', 'rgba(40, 167, 69, 0.6)', 'rgba(255, 193, 7, 0.6)' ], borderColor: [ 'rgba(0, 74, 153, 1)', 'rgba(40, 167, 69, 1)', 'rgba(255, 193, 7, 1)' ], borderWidth: 1 }] }; towingChart = new Chart(chartContext, { type: 'bar', data: data, options: { responsive: true, maintainAspectRatio: true, scales: { y: { beginAtZero: true, title: { display: true, text: 'Weight (lbs)' } } }, plugins: { title: { display: true, text: 'Weight Comparison' }, legend: { display: false // Simplified legend, labels are clear } } } }); } function validateInput(input, errorElement, minValue, maxValue) { var value = input.value.trim(); if (value === "") { errorElement.textContent = "This field cannot be empty."; errorElement.classList.add('visible'); return false; } var numValue = parseFloat(value); if (isNaN(numValue)) { errorElement.textContent = "Please enter a valid number."; errorElement.classList.add('visible'); return false; } if (numValue < 0) { errorElement.textContent = "Value cannot be negative."; errorElement.classList.add('visible'); return false; } if (minValue !== undefined && numValue maxValue) { errorElement.textContent = "Value cannot exceed " + maxValue + "."; errorElement.classList.add('visible'); return false; } errorElement.textContent = ""; errorElement.classList.remove('visible'); return true; } function calculateHitchWeight() { var trailerWeight = parseFloat(trailerWeightInput.value); var trailerTongueWeight = parseFloat(trailerTongueWeightInput.value); var towVehicleMaxTongueWeight = parseFloat(towVehicleMaxTongueWeightInput.value); var towVehicleMaxTrailerWeight = parseFloat(towVehicleMaxTrailerWeightInput.value); var isValid = true; isValid = validateInput(trailerWeightInput, trailerWeightError, 0) && isValid; isValid = validateInput(trailerTongueWeightInput, trailerTongueWeightError, 0) && isValid; isValid = validateInput(towVehicleMaxTongueWeightInput, towVehicleMaxTongueWeightError, 0) && isValid; isValid = validateInput(towVehicleMaxTrailerWeightInput, towVehicleMaxTrailerWeightError, 0) && isValid; if (!isValid) { mainResultDiv.textContent = "– %"; actualTongueWeightSpan.textContent = "– lbs"; calculatedTongueWeightPercentSpan.textContent = "– %"; weightLimitStatusDiv.textContent = "Invalid Input"; updateTableData('–', '–', '–', '–', '–', '–', '–', '–', '–', '–', '–', '–'); updateChart(0, 0, 0, 0); // Clear chart or show default state return; } var tongueWeightPercent = (trailerTongueWeight / trailerWeight) * 100; var actualTongueWeight = trailerTongueWeight; // Already have this mainResultDiv.textContent = tongueWeightPercent.toFixed(1) + " %"; actualTongueWeightSpan.textContent = actualTongueWeight.toFixed(0) + " lbs"; calculatedTongueWeightPercentSpan.textContent = tongueWeightPercent.toFixed(1) + " %"; var statusMessage = ""; var tongueWeightStatus = ""; var tonguePercentStatus = ""; var maxTongueStatus = ""; var maxTrailerStatus = ""; var trailerWeightForChart = trailerWeight; // Assuming GVWR represents loaded trailer weight for chart comparison if (trailerTongueWeight 0.15 && trailerWeightInput.id === 'trailerWeight') { // Assuming travel trailer default tonguePercentStatus = "High (Stability OK)"; } else if (tongueWeightPercent > 0.25 && trailerWeightInput.id !== 'trailerWeight') { // Assuming fifth wheel if not travel trailer ID tonguePercentStatus = "High (Stability OK)"; } else { tonguePercentStatus = "Ideal Range"; } if (actualTongueWeight > towVehicleMaxTongueWeight) { maxTongueStatus = "Exceeded!"; statusMessage = "OVER LIMIT"; } else { maxTongueStatus = "Within Limit"; } if (trailerWeightValue > towVehicleMaxTrailerWeight) { maxTrailerStatus = "Exceeded!"; if (statusMessage !== "OVER LIMIT") statusMessage = "OVER LIMIT"; } else { maxTrailerStatus = "Within Limit"; } if (statusMessage === "") { statusMessage = "Within Limits"; } weightLimitStatusDiv.textContent = statusMessage; updateTableData(actualTongueWeight, tongueWeightPercent, towVehicleMaxTongueWeight, towVehicleMaxTrailerWeight, tongueWeightStatus, tonguePercentStatus, maxTongueStatus, maxTrailerStatus); updateChart(tongueWeightPercent, trailerWeightForChart, towVehicleMaxTrailerWeight, towVehicleMaxTongueWeight); } function updateTableData(actualTW, calcPercent, maxTW, maxTWT) { tableTongueWeightCell.textContent = actualTW.toFixed(0) + " lbs"; tableTonguePercentCell.textContent = calcPercent.toFixed(1) + " %"; tableMaxTongueCell.textContent = maxTW.toFixed(0) + " lbs"; tableMaxTrailerCell.textContent = maxTWT.toFixed(0) + " lbs"; var tonguePercent = parseFloat(calcPercent); var actualTWValue = parseFloat(actualTW); var maxTWValue = parseFloat(maxTW); var maxTWTValue = parseFloat(maxTWT); var currentTrailerWeight = parseFloat(trailerWeightInput.value); // Determine status text more robustly var tonguePercentStatusText = ""; if (isNaN(currentTrailerWeight) || currentTrailerWeight <= 0) { tonguePercentStatusText = "N/A"; } else if (tonguePercent 15 && trailerWeightInput.id === 'trailerWeight') { // Assuming travel trailer by default if trailerWeight is used tonguePercentStatusText = "High (Check Load)"; } else if (tonguePercent > 25) { // Assuming fifth wheel if not travel trailer by ID tonguePercentStatusText = "High (Check Load)"; } else { tonguePercentStatusText = "Ideal"; } var actualTWStatusText = ""; if (actualTWValue > maxTWValue) { actualTWStatusText = "Exceeded!"; } else { actualTWStatusText = "OK"; } var maxTWTStatusText = ""; if (maxTWTValue maxTWTValue) { maxTWTStatusText = "Exceeded!"; } else { maxTWTStatusText = "OK"; } tableTonguePercentStatusCell.textContent = tonguePercentStatusText; tableTongueWeightStatusCell.textContent = actualTWStatusText; tableMaxTongueStatusCell.textContent = actualTWStatusText; // Status for tow vehicle max tongue weight tableMaxTrailerStatusCell.textContent = maxTWTStatusText; } function copyResults() { var mainResult = mainResultDiv.textContent; var actualTW = actualTongueWeightSpan.textContent; var calcPercent = calculatedTongueWeightPercentSpan.textContent; var limitsStatus = weightLimitStatusDiv.textContent; var tableRows = document.querySelectorAll('.results-table tbody tr'); var tableData = "Towing Capacity Summary:\n"; tableRows.forEach(function(row) { var cells = row.querySelectorAll('td'); if (cells.length === 3) { tableData += cells[0].textContent + ": " + cells[1].textContent + " (" + cells[2].textContent + ")\n"; } }); var assumptions = "Key Assumptions:\n"; assumptions += "- Trailer GVWR: " + trailerWeightInput.value + " lbs\n"; assumptions += "- Trailer Tongue Weight: " + trailerTongueWeightInput.value + " lbs\n"; assumptions += "- Tow Vehicle Max Tongue Weight: " + towVehicleMaxTongueWeightInput.value + " lbs\n"; assumptions += "- Tow Vehicle Max Trailer Weight: " + towVehicleMaxTrailerWeightInput.value + " lbs\n"; var textToCopy = "Hitch Weight Calculator Results:\n\n"; textToCopy += "Primary Result: " + mainResult + "\n"; textToCopy += "Actual Tongue Weight: " + actualTW + "\n"; textToCopy += "Calculated Percentage: " + calcPercent + "\n"; textToCopy += "Overall Status: " + limitsStatus + "\n\n"; textToCopy += tableData + "\n"; textToCopy += assumptions; if (navigator.clipboard) { navigator.clipboard.writeText(textToCopy).then(function() { alert('Results copied to clipboard!'); }).catch(function(err) { console.error('Failed to copy: ', err); fallbackCopyTextToClipboard(textToCopy); }); } else { fallbackCopyTextToClipboard(textToCopy); } } function fallbackCopyTextToClipboard(text) { var textArea = document.createElement("textarea"); textArea.value = text; textArea.style.position = "fixed"; textArea.style.left = "-9999px"; textArea.style.top = "-9999px"; document.body.appendChild(textArea); textArea.focus(); textArea.select(); try { var successful = document.execCommand('copy'); var msg = successful ? 'successful' : 'unsuccessful'; alert('Results copied to clipboard! (' + msg + ')'); } catch (err) { alert('Oops, unable to copy'); } document.body.removeChild(textArea); } function resetCalculator() { trailerWeightInput.value = "7500"; trailerTongueWeightInput.value = "900"; towVehicleMaxTongueWeightInput.value = "1000"; towVehicleMaxTrailerWeightInput.value = "10000"; // Clear errors trailerWeightError.textContent = ""; trailerWeightError.classList.remove('visible'); trailerTongueWeightError.textContent = ""; trailerTongueWeightError.classList.remove('visible'); towVehicleMaxTongueWeightError.textContent = ""; towVehicleMaxTongueWeightError.classList.remove('visible'); towVehicleMaxTrailerWeightError.textContent = ""; towVehicleMaxTrailerWeightError.classList.remove('visible'); calculateHitchWeight(); } // Initial calculation on load with default values document.addEventListener('DOMContentLoaded', function() { resetCalculator(); // Manually trigger the calculation after reset to populate results calculateHitchWeight(); }); // Add event listeners for real-time updates trailerWeightInput.addEventListener('input', calculateHitchWeight); trailerTongueWeightInput.addEventListener('input', calculateHitchWeight); towVehicleMaxTongueWeightInput.addEventListener('input', calculateHitchWeight); towVehicleMaxTrailerWeightInput.addEventListener('input', calculateHitchWeight); // Initial chart rendering setup var towingChartCanvas = document.getElementById('towingChart'); if (towingChartCanvas) { towingChartCanvas.width = towingChartCanvas.offsetWidth; // Set canvas width based on its display size towingChartCanvas.height = towingChartCanvas.offsetHeight || 300; // Set a default height if none is set updateChart(0, 0, 0, 0); // Initial empty chart }

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