Trailer Tongue Weight Calculator
Enter the loaded trailer weight and either your tongue scale reading or a target percentage. You get the recommended tongue weight range, your actual percentage with a clear pass or fail, checks against hitch and vehicle ratings, and how far to shift cargo if it is out of range.
Last updated:
Everything on the trailer, as you will tow it (from a scale ticket if possible).
Blank = middle of the range (12% conventional, 20% fifth wheel).
Any unit, same as B.
Support = the brick or block at the other end of the beam.
Lowest of receiver, ball mount and ball ratings.
From the owner's manual.
Used to suggest how far to shift it if the check fails.
How to use the Trailer Tongue Weight Calculator
- Choose whether you want to check a measured tongue weight or find the target.
- Pick the trailer type and enter the loaded trailer weight.
- Enter the tongue reading from a tongue scale, or use the bathroom-scale lever method with the two distances.
- Optionally add your hitch and vehicle tongue ratings and the axle-to-coupler distance.
- Press Check tongue weight and follow the pass/fail result and cargo move suggestion.
Tongue weight formulas
- Tongue weight % = tongue weight ÷ loaded trailer weight × 100
- Recommended range = trailer weight × 10% to 15% (bumper-pull) or × 15% to 25% (fifth wheel / gooseneck)
- Lever (bathroom scale) method = scale reading × (A + B) ÷ B
- Effect of moving cargo: moving a load of weight W a distance d toward the coupler adds about W × d ÷ L to the tongue, where L is the distance from the axle center to the coupler.
Recommended tongue weight by trailer weight
| Loaded trailer | Bumper-pull 10–15% | Fifth wheel 15–25% |
|---|---|---|
| 1,500 lb | 150 – 225 lb | — |
| 3,000 lb | 300 – 450 lb | — |
| 5,000 lb | 500 – 750 lb | 750 – 1,250 lb |
| 7,500 lb | 750 – 1,125 lb | 1,125 – 1,875 lb |
| 10,000 lb | 1,000 – 1,500 lb | 1,500 – 2,500 lb |
| 15,000 lb | — | 2,250 – 3,750 lb |
Typical receiver hitch class ratings
These are common nominal limits. The rating stamped on your receiver, ball mount and ball, and the limit in your vehicle's manual, always take priority.
| Class | Max trailer weight | Max tongue weight |
|---|---|---|
| Class I | up to 2,000 lb | 200 lb |
| Class II | up to 3,500 lb | 350 lb |
| Class III | up to 8,000 lb | 800 lb |
| Class IV | up to 10,000 lb | 1,000 lb |
| Class V | about 12,000 – 20,000 lb | about 1,200 – 2,700 lb |
Loading tips
- Load about 60% of the cargo weight in front of the trailer axle, with heavy items low and centered side to side.
- Weigh the trailer loaded the way you will travel: water tanks, propane, batteries and gear all count.
- Re-check after big changes, such as adding a generator to the front or bikes to a rear bumper rack, which lowers tongue weight.
Frequently asked questions
How much tongue weight should a trailer have?
For a conventional bumper-pull trailer, the widely used guideline is 10% to 15% of the loaded trailer weight. A 5,000 lb trailer should put about 500 to 750 lb on the hitch ball. Fifth-wheel and gooseneck trailers typically carry 15% to 25% on the pin or ball.
What happens if tongue weight is too light?
Too little tongue weight, generally under about 10%, makes a trailer much more likely to sway, which can become dangerous at highway speeds. Move heavy cargo forward of the trailer axle to increase it.
What happens if tongue weight is too heavy?
Too much tongue weight overloads the hitch and the tow vehicle's rear axle, lifts weight off the front wheels and can reduce steering and braking control. It can also exceed the hitch or vehicle tongue rating. Move cargo rearward or use a weight-distribution hitch where appropriate.
How do I measure tongue weight with a bathroom scale?
For light tongues, rest the coupler on the scale at normal towing height. For heavier ones, lay a sturdy beam across a block and the scale, rest the tongue jack on the beam, and measure the distances. Tongue weight = scale reading × (A + B) ÷ B, where A is tongue to scale and B is tongue to block. With the tongue 1 ft from the scale and 2 ft from the block, multiply the reading by 1.5.
How do I calculate tongue weight percentage?
Divide the tongue weight by the total loaded trailer weight and multiply by 100. For example, 520 lb on the tongue of a 5,000 lb trailer is 520 ÷ 5,000 × 100 = 10.4%.
Does tongue weight count against my truck's payload?
Yes. Tongue weight is carried by the tow vehicle, so it counts toward payload and the vehicle's GVWR along with passengers and cargo. Check the full picture with a towing capacity calculator.
Is this a substitute for my vehicle and hitch ratings?
No. It applies common guidelines. Always follow the tow vehicle manufacturer's and hitch maker's ratings and instructions, which take priority over any general rule.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.