Towing Safety Calculator
Use this calculator to determine if your tow vehicle and trailer combination is within safe operating limits for Gross Vehicle Weight Rating (GVWR), Gross Combined Weight Rating (GCWR), and Tongue Weight.
Towing Safety Analysis:
Fill in all fields and click "Calculate" to see your results.
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.calculator-results {
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.calculator-results .status-ok {
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function calculateTowingSafety() {
var vehicleGVWR = parseFloat(document.getElementById("vehicleGVWR").value);
var vehicleGCWR = parseFloat(document.getElementById("vehicleGCWR").value);
var vehicleCurbWeight = parseFloat(document.getElementById("vehicleCurbWeight").value);
var trailerGrossWeight = parseFloat(document.getElementById("trailerGrossWeight").value);
var tongueWeightPercentage = parseFloat(document.getElementById("tongueWeightPercentage").value);
var vehicleOccupantsCargo = parseFloat(document.getElementById("vehicleOccupantsCargo").value);
var resultsDiv = document.getElementById("towingResults");
resultsDiv.innerHTML = ""; // Clear previous results
// Input validation
if (isNaN(vehicleGVWR) || isNaN(vehicleGCWR) || isNaN(vehicleCurbWeight) ||
isNaN(trailerGrossWeight) || isNaN(tongueWeightPercentage) || isNaN(vehicleOccupantsCargo) ||
vehicleGVWR < 0 || vehicleGCWR < 0 || vehicleCurbWeight < 0 ||
trailerGrossWeight < 0 || tongueWeightPercentage < 0 || vehicleOccupantsCargo 100) {
resultsDiv.innerHTML = "Tongue Weight Percentage cannot exceed 100%.";
return;
}
// 1. Calculate Tongue Weight
var calculatedTongueWeight = trailerGrossWeight * (tongueWeightPercentage / 100);
// 2. Calculate Actual Gross Vehicle Weight (GVW)
// GVW = Vehicle Curb Weight + Occupants/Cargo + Trailer Tongue Weight
var actualVehicleWeight = vehicleCurbWeight + vehicleOccupantsCargo + calculatedTongueWeight;
// 3. Calculate Actual Gross Combined Weight (GCW)
// GCW = Vehicle Curb Weight + Occupants/Cargo + Trailer Gross Weight
var actualCombinedWeight = vehicleCurbWeight + vehicleOccupantsCargo + trailerGrossWeight;
// 4. Calculate Remaining Payload Capacity
var remainingPayload = vehicleGVWR – actualVehicleWeight;
// 5. Safety Checks
var gvwrStatus = "";
var gcwrStatus = "";
var tongueWeightStatus = "";
var overallStatus = "status-ok";
if (actualVehicleWeight > vehicleGVWR) {
gvwrStatus = "
EXCEEDED!";
overallStatus = "status-danger";
} else {
gvwrStatus = "
OK";
}
if (actualCombinedWeight > vehicleGCWR) {
gcwrStatus = "
EXCEEDED!";
if (overallStatus !== "status-danger") { // Prioritize danger over warning
overallStatus = "status-danger";
}
} else {
gcwrStatus = "
OK";
}
// Tongue weight guideline (10-15% of GTW)
var minTongueWeight = trailerGrossWeight * 0.10;
var maxTongueWeight = trailerGrossWeight * 0.15;
if (calculatedTongueWeight maxTongueWeight) {
tongueWeightStatus = "
OUT OF RECOMMENDED RANGE! (Recommended: " + minTongueWeight.toFixed(0) + " – " + maxTongueWeight.toFixed(0) + " lbs)";
if (overallStatus === "status-ok") { // Only downgrade to warning if not already danger
overallStatus = "status-warning";
}
} else {
tongueWeightStatus = "
Within Recommended Range";
}
// Display Results
var resultsHTML = "
Towing Safety Analysis:
";
resultsHTML += "
Calculated Tongue Weight: " + calculatedTongueWeight.toFixed(0) + " lbs
";
resultsHTML += "
Tongue Weight Status: " + tongueWeightStatus + "
";
resultsHTML += "
Actual Gross Vehicle Weight (GVW): " + actualVehicleWeight.toFixed(0) + " lbs
";
resultsHTML += "
Tow Vehicle GVWR: " + vehicleGVWR.toFixed(0) + " lbs
";
resultsHTML += "
GVWR Compliance: " + gvwrStatus + "
";
resultsHTML += "
Remaining Payload Capacity: " + remainingPayload.toFixed(0) + " lbs
";
resultsHTML += "
Actual Gross Combined Weight (GCW): " + actualCombinedWeight.toFixed(0) + " lbs
";
resultsHTML += "
Tow Vehicle GCWR: " + vehicleGCWR.toFixed(0) + " lbs
";
resultsHTML += "
GCWR Compliance: " + gcwrStatus + "
";
resultsHTML += "";
if (overallStatus === "status-ok") {
resultsHTML += "Your towing setup appears to be within safe limits based on the provided data.";
} else if (overallStatus === "status-warning") {
resultsHTML += "Warning: Your tongue weight is outside the recommended 10-15% range. This can affect stability and safety.";
} else {
resultsHTML += "Danger: Your towing setup EXCEEDS one or more critical weight ratings. Do NOT tow until corrected!";
}
resultsHTML += "";
resultsDiv.innerHTML = resultsHTML;
}
Understanding Towing Terminology
Towing safely requires understanding several key weight ratings and measurements. Exceeding any of these limits can lead to dangerous driving conditions, vehicle damage, and legal issues.
Gross Vehicle Weight Rating (GVWR)
The maximum permissible total weight of your fully loaded tow vehicle, including the vehicle itself, all passengers, cargo, and the downward force (tongue weight) exerted by the trailer on the hitch. This rating is set by the vehicle manufacturer and is typically found on a sticker inside the driver's side door jamb.
Gross Combined Weight Rating (GCWR)
The maximum permissible total weight of the entire combination of the tow vehicle and the fully loaded trailer. This includes the tow vehicle's curb weight, all occupants and cargo in the vehicle, and the entire weight of the loaded trailer. The GCWR is a critical limit for the vehicle's powertrain, brakes, and chassis. It's usually found in your vehicle's owner's manual.
Tow Vehicle Curb Weight
This is the weight of your vehicle as it left the factory, including a full tank of fuel and all standard equipment, but without any passengers, cargo, or accessories. You can find this in your owner's manual or on the manufacturer's website.
Trailer Gross Weight (GTW)
The total weight of your trailer when it's fully loaded with all your gear, water, and supplies. This is the actual weight that would be measured if you put the loaded trailer on a scale. It's crucial to know this weight to ensure you don't exceed your vehicle's towing capacity.
Tongue Weight (TW)
The downward force that the trailer's coupler exerts on the hitch ball of the tow vehicle. For conventional trailers, the recommended tongue weight is typically 10-15% of the trailer's gross weight. Too little tongue weight can cause trailer sway, while too much can overload the tow vehicle's rear axle and reduce steering control. It's important to measure or calculate this accurately.
Payload Capacity
This is the maximum amount of weight your tow vehicle can carry, including passengers, cargo, and the trailer's tongue weight. It's calculated by subtracting the vehicle's curb weight from its GVWR. Every pound added to the vehicle (including the tongue weight) reduces the available payload.
How to Use This Calculator
- Find Your Vehicle's GVWR and GCWR: Look for stickers on your driver's side door jamb or consult your owner's manual.
- Determine Your Vehicle's Curb Weight: This is usually in your owner's manual or manufacturer's specifications.
- Weigh Your Loaded Trailer: The most accurate way to get your Trailer Gross Weight is to weigh it at a truck stop or public scale.
- Estimate Occupants & Cargo: Add up the weight of all passengers and cargo you'll be carrying inside the tow vehicle.
- Enter Desired Tongue Weight Percentage: The calculator uses this to estimate your tongue weight. Aim for 10-15%.
- Click "Calculate": The calculator will provide an analysis of your setup, highlighting any areas where you might be exceeding limits or operating outside recommended ranges.
Always prioritize safety. If your calculations show you are exceeding any limits, adjust your loading, consider a lighter trailer, or use a more capable tow vehicle.