Towing and Payload
Front and Rear Axle Load Calculator
Estimate how an added load changes front and rear axle weights. Loads behind the rear axle can remove weight from the front axle, so rear share may exceed 100 percent.
Replace the example values
Check labels, prefixes, suffixes, and percentage bases before calculating.
Establish the comparison first
Estimate how an added load changes front and rear axle weights — a remaining margin is useful only when every entered weight belongs to the same loaded setup.
Loads behind the rear axle can remove weight from the front axle, so rear share may exceed 100 percent — that condition defines when projected front axle load is comparable with another result.
This number does not replace independent checks of axle, tire, hitch, roof, component, or manufacturer limits that apply to the loaded vehicle — for added load, the page specifically expects cargo or tongue weight added after measurement.
When the vehicle decision also requires you to compare current vertical load with the lower hitch and vehicle limit, calculate it independently with the Remaining Hitch Capacity.
Keep these measurements together
Measured front axle is defined here as front axle scale weight before additions — keeping that definition intact requires you to use the same loaded condition for every weight and retain the scale ticket or rating source.
For Measured rear axle, use the quantity described as rear axle scale weight before additions — in the vehicle record, use the same loaded condition for every weight and retain the scale ticket or rating source.
Added load: Cargo or tongue weight added after measurement — a compatible entry should use the same loaded condition for every weight and retain the scale ticket or rating source.
The Added load carried by rear axle entry represents estimated rear-axle share of the added load — before calculating, keep the percentage basis explicit and do not mix a decimal fraction with a percent value.
Working through the equation
In “projected axle load = measured axle load + assigned share of added load,” the equation links measured front axle, measured rear axle, and added load to projected front axle load.
No term beyond measured front axle, measured rear axle, added load, and added load carried by rear axle is introduced in “projected axle load = measured axle load + assigned share of added load.”
How the values should be read
Projected front axle load answers “Estimate how an added load changes front and rear axle weights.” The additional display, Projected rear axle load, is a different view of the same entered measurements.
Scale the completed setup for a reliable axle check — when that condition changes, compare separate calculator runs instead of blending the inputs.
Because loads behind the rear axle can remove weight from the front axle, so rear share may exceed 100 percent, a disagreement between projected front axle load and an outside reference should trigger a review of measured front axle and added load carried by rear axle.
Build another useful comparison to estimate loaded trailer weight including cargo and fresh water with the Loaded Trailer Weight.
Questions about the operating case
What measurement source fits Measured front axle when it represents front axle scale weight before additions?
Because measured front axle represents front axle scale weight before additions, use a source tied to the exact vehicle, component, and operating period described by the other fields.
How does the warning “Loads behind the rear axle can remove weight from the front axle, so rear share may exceed 100 percent” affect Projected front axle load?
The condition “Loads behind the rear axle can remove weight from the front axle, so rear share may exceed 100 percent” is not corrected automatically by the numeric inputs, so create a separate front and rear axle load case when it changes.
What assumption is expressed by “projected axle load = measured axle load + assigned share of added load”?
In “projected axle load = measured axle load + assigned share of added load,” measured front axle and measured rear axle are treated as parts of one vehicle case.
How narrowly is Measured rear axle defined by “Rear axle scale weight before additions”?
The definition “Rear axle scale weight before additions” excludes a similarly named rating or a measurement taken at another reference point.