Trailer Tongue Weight Calculator

Check trailer inputs

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Measurement method:

Direct scale, bathroom-scale lever, vehicle-scale delta, or target estimate.

Trailer profile:

Use a preset to start close to the trailer type, target band, and ratings.

Weight unit:

Use the same unit as your trailer sticker, hitch rating, or scale ticket.

Loaded trailer weight:

The target tongue range is calculated from this loaded gross trailer weight.

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Tow vehicle only weight:

Record the tow vehicle by itself on the scale.

Tow vehicle hitched weight:

The hitched tow-vehicle reading must be higher than the vehicle-only reading.

Target tongue percent:

Use the trailer manufacturer's target if it differs from the default midpoint.

Target slider {{ formatPercent(targetPercentValue, 1) }}

Hitch tongue rating:

This check compares the measured or estimated tongue load against the hitch limit.

Payload available for tongue and rear cargo:

Use the remaining tow-vehicle payload that can still carry hitch load and cargo behind the rear axle.

Tow-vehicle cargo behind rear axle:

Enter 0 when no cargo is carried behind the rear axle.

Lower target band:

Adjust only when the trailer manufacturer specifies a different band.

Upper target band:

Keep the band aligned with the trailer maker's guidance when available.

Bathroom lever multiplier:

Used only when bathroom-scale lever mode is selected.

Distance unit:

Use the same distance unit for cargo movement and axle-to-coupler distance.

Movable cargo weight:

Estimate the cargo you can safely shift along the trailer deck.

Planned cargo shift distance:

Used to estimate one practical cargo movement step in the scenario table.

Coupler-to-axle distance:

Used only for cargo-shift scenario estimates.

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Scenario	Desired tongue	Gap from current	Cargo shift note	Copy
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Tongue weight is the downward load a trailer places on the hitch ball or coupler. For a conventional bumper-pull trailer, that load is a small but important share of the loaded trailer weight. Too little tongue weight can let the trailer sway because the load is balanced too far rearward. Too much tongue weight can overload the hitch, receiver, rear axle, tires, or tow-vehicle payload before the trailer reaches its advertised towing limit.

The useful number is based on the trailer as it will actually travel. Dry weight, brochure weight, and empty curb weight do not include water, propane, batteries, tools, food, luggage, equipment, or cargo. A trailer that looks within limits on paper can still become unsafe after tanks are filled or heavy gear is moved behind the axle.

Many travel, utility, equipment, and enclosed cargo trailers use a target near 10 to 15 percent of loaded trailer weight, while some boat trailers use a lighter range. The trailer maker's guidance wins when it differs. The same loaded trailer can also need a separate weight-distribution hitch check, because cargo behind the tow vehicle rear axle adds to the load the hitch bars must handle.

Tongue weight is not a substitute for the full towing checklist. It should be read with gross trailer weight, gross vehicle weight rating, rear axle rating, tire ratings, receiver and ball-mount ratings, payload remaining, brake setup, and load security. The calculation helps find an obvious mismatch before towing, but the final check is a measured, fully loaded setup.

How to Use This Tool:

Start with the trailer as loaded for travel, then choose the measurement path that matches the scale information you have.

Choose Measurement method. Use direct scale when you have a tongue scale or coupler reading, bathroom lever when a lever setup multiplies a household scale reading, vehicle scale delta when you have two tow-vehicle scale tickets, or estimate mode for planning.
Select a Trailer profile to load realistic starting values, then change Loaded trailer weight to the actual loaded gross trailer weight.
Enter the tongue reading fields for the selected method. Vehicle scale mode requires Tow vehicle only weight and Tow vehicle hitched weight, with trailer wheels off the scale for the hitched reading.
Set Target tongue percent and the lower and upper target band in Advanced when the trailer maker specifies a different range.
Enter Hitch tongue rating, Payload available, and Tow-vehicle cargo behind rear axle so the rating checks reflect the full tow setup.
Use the Advanced cargo-shift fields when you want a rough estimate of how moving a known cargo weight forward or rearward changes tongue load.
Read Tongue Load Check first, then Towing Limits, Load Shift Scenarios, Tongue Weight Band, and JSON.

If a warning appears, fix the loaded trailer weight, the selected measurement reading, the target band order, or the rating fields before treating the result as usable.

Interpreting Results:

Measured tongue weight or Estimated tongue weight is the current downward coupler load. Target tongue range is the selected percent band multiplied by loaded trailer weight. A Light tongue result points toward rear-heavy loading and sway risk. A Heavy tongue result points toward hitch, payload, rear-axle, or tire overload risk.

Trailer tongue weight result cues and checks
Result cue	What to check	What not to overread
Within band	Confirm hitch rating, payload margin, axle ratings, and loaded tire pressures.	It does not prove the tow vehicle or trailer is within every rating.
Light tongue	Move cargo forward, verify tanks and storage compartments, then re-weigh.	Do not fix sway by guessing at cargo movement without a new measurement.
Heavy tongue	Move cargo rearward only if the trailer maker allows it and the trailer remains stable.	Reducing tongue weight cannot exceed axle, tire, gross, or hitch limits.
Hitch or payload over	Use the lowest rated receiver, ball mount, ball, vehicle, and payload number.	A weight-distribution hitch does not create extra vehicle payload.

Load Shift Scenarios are planning estimates. They assume a simple lever around the axle group and cannot model suspension movement, multiple axles, tank slosh, shifting cargo, or trailer-specific weight-distribution geometry.

Technical Details:

Tongue weight is a static vertical load at the coupler. The target percent compares that load with the loaded trailer weight, not empty weight. The same measured load also consumes tow-vehicle payload, and rear cargo carried behind the tow vehicle axle can be added when selecting weight-distribution bars.

The measurement path changes only how the current tongue load is obtained. Direct mode uses the entered tongue scale reading. Bathroom lever mode multiplies the scale reading by the lever multiplier. Vehicle scale mode subtracts the tow-vehicle-only scale ticket from the hitched tow-vehicle scale ticket. Estimate mode skips measurement and uses the selected target percent.

Formula Core:

The main equations keep all weights in the selected unit, with percent values divided by 100.

\begin{array}{lcl} target tongue weight & = & loaded trailer weight \times \frac{target percent}{100} \\ tongue percent & = & \frac{current tongue weight}{loaded trailer weight} \times 100 \\ vehicle scale tongue & = & hitched tow-vehicle weight - tow-vehicle-only weight \\ weight-distribution sizing load & = & current tongue weight + rear cargo behind axle \end{array}

Trailer tongue weight measurement rules
Measurement method	Current tongue load rule	Common mistake
Direct scale	Use the entered coupler or jack-point reading.	Weighing an unloaded trailer or leaving travel cargo out.
Bathroom lever	Scale reading multiplied by the selected lever multiplier.	Entering the already multiplied tongue weight as the scale reading.
Vehicle scale delta	Hitched tow-vehicle weight minus tow-vehicle-only weight.	Letting trailer axles sit on the scale during the hitched tow-vehicle reading.
Target estimate	Loaded trailer weight multiplied by selected target percent.	Treating a planning estimate as a replacement for a scale reading.

For cargo movement, the lever estimate is movable cargo weight x shift distance / coupler-to-axle distance. Moving cargo forward increases tongue load; moving it rearward decreases tongue load. The estimate is useful for understanding direction and order of magnitude, then the trailer should be re-weighed.

Safety And Accuracy Notes:

This is a planning and checking aid, not a replacement for trailer, tow-vehicle, hitch, tire, axle, brake, and weight-distribution manufacturer instructions. Verify every rating from labels or manuals, use the lowest applicable rating, and re-weigh after changing tanks, cargo, passengers, or hitch setup.

Bathroom-scale lever readings depend on a correct lever layout, level trailer attitude, stable support, and wheel chocks.
Vehicle-scale differences can be distorted by different fuel, passenger, cargo, or trailer wheel placement between scale tickets.
Boat trailers, specialty trailers, fifth-wheel pin weight, and gooseneck pin weight can use different targets than conventional ball-mounted trailers.

Worked Examples:

Travel trailer in range:

A 5,200 lb loaded trailer with a 650 lb direct tongue reading has a Measured tongue weight of 650 lb and a tongue percent of 12.5%. With a 10% to 15% band, the Target tongue range is 520 to 780 lb, so the tongue load is inside the selected band before hitch and payload margins are checked.

Bathroom lever reading:

A lever setup with a 210 lb household scale reading and a Bathroom lever multiplier of 3 produces a 630 lb tongue estimate. If that reading is for the fully loaded trailer, the result can be compared with the target band and hitch rating, then confirmed with a more direct scale when possible.

Payload over even with a good percent:

A trailer can show Within band while Payload margin is negative. For example, 700 lb of tongue load plus 150 lb behind the tow vehicle rear axle consumes 850 lb of remaining payload. If only 760 lb remains, the payload check is over by 90 lb even though the tongue percentage may look normal.

FAQ:

Should I use trailer dry weight?

No. Use loaded trailer weight with normal travel cargo, tanks, accessories, and gear included. The target band is only meaningful when the weight matches the real tow condition.

Why can the hitch pass while payload fails?

The hitch rating checks the towing hardware. Payload margin checks how much tow-vehicle carrying capacity remains after tongue load and rear cargo are added.

What does estimate mode do?

Estimate mode multiplies loaded trailer weight by the selected target percent. It is useful before loading or shopping, but it should be replaced by a measured tongue weight before towing.

Can moving cargo fix every tongue-weight problem?

No. Cargo movement must stay within trailer loading instructions and all vehicle, axle, tire, gross, hitch, and payload ratings. Re-weigh after any meaningful shift.

Glossary:

Tongue weight: The downward force the trailer coupler places on the hitch.
Loaded trailer weight: The trailer weight as it will travel, including cargo, fluids, batteries, propane, and accessories.
Payload margin: Remaining tow-vehicle carrying capacity after tongue load and rear cargo are counted.
Weight-distribution sizing load: The tongue load plus cargo behind the tow vehicle rear axle, used as a planning load for hitch bars.

References:

NHTSA interpretation on trailer tongue weight and vehicle ratings, National Highway Traffic Safety Administration.
Tongue Weight Is Key To Safe Towing, GMC.
Trailer And Tongue Weight owner guidance excerpt, NHTSA recall investigation document collection.