Truck Axle Weight Calculator App

Truck Axle Weight Calculator

Verify Gross Weight & Axle Distribution for Federal Compliance

Steer Axle Weight (lbs)

Drive Axles Weight (lbs)

Trailer Axles Weight (lbs)

Max GVWR Limit (lbs)

How to Use the Truck Axle Weight Calculator

Operating a commercial motor vehicle requires strict adherence to weight regulations to ensure road safety and infrastructure longevity. This calculator helps drivers and fleet managers verify if their current load distribution complies with the US Federal Bridge Formula and standard weight limits.

Standard Weight Limits (US Federal)

Steer Axle: Typically limited to 12,000 lbs (though tire ratings may allow more).
Drive Tandems: Legal limit is usually 34,000 lbs.
Trailer Tandems: Legal limit is usually 34,000 lbs.
Gross Vehicle Weight: Standard maximum is 80,000 lbs without special permits.

Realistic Calculation Example

Imagine you pull onto a CAT scale and receive the following readings:

Steer: 11,800 lbs (Legal)
Drives: 35,200 lbs (Overweight by 1,200 lbs)
Trailer: 32,500 lbs (Legal)
Gross: 79,500 lbs (Legal)

In this scenario, while your Gross weight is under 80,000 lbs, you are illegal on your drive axles. You would need to slide your trailer tandems forward to shift some of that 1,200 lbs from the drives to the trailer axles.

Common Weight Distribution Issues

If you are overweight on an axle but legal on gross, you can often fix the issue by:

Sliding Tandems: Move the trailer wheels forward to put more weight on the trailer axles, or backward to put more weight on the drive axles.
Sliding the Fifth Wheel: Moving the fifth wheel forward shifts weight to the steer axle; moving it backward shifts weight to the drive axles.
Rethinking Cargo Placement: If the load is nose-heavy, it puts more pressure on the drive axles. Center the heaviest pallets over the trailer tandems or slightly forward.

function calculateAxleWeights() { var steer = parseFloat(document.getElementById('steerWeight').value) || 0; var drive = parseFloat(document.getElementById('driveWeight').value) || 0; var trailer = parseFloat(document.getElementById('trailerWeight').value) || 0; var gvwrLimit = parseFloat(document.getElementById('maxGvwr').value) || 80000; var totalGross = steer + drive + trailer; var resultDiv = document.getElementById('weightResult'); var steerLimit = 12000; var driveLimit = 34000; var trailerLimit = 34000; var steerStatus = steer > steerLimit ? 'OVERWEIGHT' : 'LEGAL'; var driveStatus = drive > driveLimit ? 'OVERWEIGHT' : 'LEGAL'; var trailerStatus = trailer > trailerLimit ? 'OVERWEIGHT' : 'LEGAL'; var grossStatus = totalGross > gvwrLimit ? 'OVERWEIGHT' : 'LEGAL'; var bgColor = (steer > steerLimit || drive > driveLimit || trailer > trailerLimit || totalGross > gvwrLimit) ? '#fdf2f2' : '#f2fdf5'; var borderColor = (steer > steerLimit || drive > driveLimit || trailer > trailerLimit || totalGross > gvwrLimit) ? '#eccaca' : '#caecda'; resultDiv.style.display = 'block'; resultDiv.style.backgroundColor = bgColor; resultDiv.style.border = '1px solid ' + borderColor; var html = '

Weight Analysis Results

'; html += ''; html += ''; html += ''; html += ''; html += ''; html += ''; html += '

Axle Group	Weight	Status
Steer Axle	' + steer.toLocaleString() + ' lbs	' + steerStatus + '
Drive Axles	' + drive.toLocaleString() + ' lbs	' + driveStatus + '
Trailer Axles	' + trailer.toLocaleString() + ' lbs	' + trailerStatus + '
Gross Vehicle Weight	' + totalGross.toLocaleString() + ' lbs	' + grossStatus + '

'; if (totalGross > gvwrLimit) { html += '⚠️ Warning: Your Gross Vehicle Weight exceeds the set limit of ' + gvwrLimit.toLocaleString() + ' lbs. You may need an overweight permit or to remove cargo.'; } else if (steer > steerLimit || drive > driveLimit || trailer > trailerLimit) { html += '💡 Tip: Your Gross Weight is legal, but one or more axles are overweight. Try sliding your tandems or fifth wheel to redistribute the load.'; } else if (totalGross > 0) { html += '✅ All weights are within standard legal limits. Safe travels!'; } resultDiv.innerHTML = html; }