# What should my tongue weight be?

Computes the tongue weight range for a trailer, 10 to 15% of the loaded trailer weight by default or the range in your manual, and the percentage a measured tongue weight is.

- Page: https://www.acalculator.org/everyday-life/tongue-weight-calculator
- JSON spec: https://www.acalculator.org/everyday-life/tongue-weight-calculator.json
- Version: 0efd44faa70e

## Default answer

Example with the default inputs (Loaded trailer weight 5,000 lb, Lowest share 10%, Highest share 15%): Aim for a tongue weight of 500 to 750 lb.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| gtw | Loaded trailer weight | The gross trailer weight: the trailer and everything loaded on it. |
| lo | Lowest share | The lowest tongue weight your manual gives, as a percent of the loaded trailer weight. |
| hi | Highest share | The highest tongue weight your manual gives, as a percent of the loaded trailer weight. |
| tw | Measured tongue weight | Your tongue weight from a scale, to see its share of the trailer weight. Leave empty to skip. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| minLb | Lowest tongue weight, lb | Loaded trailer weight × lowest share, in pounds. |
| maxLb | Highest tongue weight, lb | Loaded trailer weight × highest share, in pounds. |
| minKg | Lowest tongue weight, kg | Loaded trailer weight × lowest share, in kilograms. |
| maxKg | Highest tongue weight, kg | Loaded trailer weight × highest share, in kilograms. |
| share | Measured share | Measured tongue weight ÷ loaded trailer weight × 100, in percent. |
| verdict | Measured tongue weight is | Below, within or above the range. |

## Method

tongue weight range = loaded trailer weight × lowest share ÷ 100 to loaded trailer weight × highest share ÷ 100; measured share = tongue weight ÷ loaded trailer weight × 100.

## Assumptions

- The trailer is a conventional (bumper-pull) trailer on a ball hitch; fifth-wheel and gooseneck trailers carry a larger share.
- The default range is 10% to 15%, the common US guidance for a conventional trailer (Hyundai’s manual); too little tongue weight makes a trailer sway. Kia’s US manual caps it at 10% and NSW Government gives about 5 to 10%. Set the range and the maximum tongue load your own manual gives.

## Worked examples

1. gtw = 2,267.96185, lo = 10%, hi = 15% gives minLb = 500, maxLb = 750, minKg = 226.796185, maxKg = 340.194278. Source: 1 lb = 0.45359237 kg (NIST SP 811); Hyundai owner’s manual, If You Decide to Pull a Trailer: the tongue load measured at the hitch when fully loaded should be within 10–15% of the total weight of the trailer, https://ownersmanual.hyundai.com/full_webhelp/LX3/2026/en_US/topic_snf_hxj_x5b.html (retrieved 2026-10-18).
2. gtw = 1,587.573295, lo = 10%, hi = 15%, tw = 136.077711 gives minLb = 350, maxLb = 525, share = 8.571429, verdict = below the range. Source: Hyundai owner’s manual, If You Decide to Pull a Trailer: the tongue load measured at the hitch when fully loaded should be within 10–15% of the total weight of the trailer, https://ownersmanual.hyundai.com/full_webhelp/LX3/2026/en_US/topic_snf_hxj_x5b.html (retrieved 2026-10-18).
3. gtw = 2,000, lo = 10%, hi = 15%, tw = 250 gives minKg = 200, maxKg = 300, share = 12.5, verdict = within the range. Source: Hyundai owner’s manual, If You Decide to Pull a Trailer: the tongue load measured at the hitch when fully loaded should be within 10–15% of the total weight of the trailer, https://ownersmanual.hyundai.com/full_webhelp/LX3/2026/en_US/topic_snf_hxj_x5b.html (retrieved 2026-10-18); Kia owner’s manual (KA4, 2024, US), If you do decide to pull a trailer: tongue weight at most 10% of the loaded trailer weight, https://ownersmanual.kia.com/full_webhelp/KA4/2024/en_US/topics/t00397.html (retrieved 2026-10-18); NSW Government, Towing a trailer or caravan: as a general rule, the vehicle should carry about 5 to 10% of the loaded trailer’s mass at the coupling, https://www.nsw.gov.au/driving-boating-and-transport/roads-safety-and-rules/vehicle-safety-and-compliance/towing-a-caravan (retrieved 2026-10-18).

## FAQ

### How do I calculate tongue weight?

Multiply the loaded trailer weight by 10% and by 15%, the common US range for a conventional trailer. For a 5,000 lb trailer, the tongue weight should be between 5,000 × 0.10 = 500 lb and 5,000 × 0.15 = 750 lb. If your manual gives other shares, use those.

### How do I work out my tongue weight percentage?

Divide the measured tongue weight by the loaded trailer weight and multiply by 100. A 300 lb tongue on a 3,500 lb trailer is 300 ÷ 3,500 × 100 = 8.6%, which is below 10%.

### What happens if the tongue weight is too light?

Too little weight on the hitch makes the trailer more likely to sway. Move load forward of the trailer axle, then weigh the tongue again.

### What happens if the tongue weight is too heavy?

Too much weight on the hitch overloads the rear axle of the tow vehicle and takes weight off the front wheels, which can hurt steering and braking. Move load back toward the axle, and never go over the vehicle’s maximum tongue load or GVWR.

### How do I measure tongue weight?

Use a tongue weight scale under the coupler. Or use a public vehicle scale: weigh the tow vehicle alone, then again with the loaded trailer hitched but its wheels off the scale. The gain in the vehicle’s total weight is the tongue weight. Weigh it loaded as you will travel.

### Does every vehicle use 10 to 15%?

No. Kia’s US manual caps tongue weight at 10% for its vehicles, and NSW Government in Australia gives about 5 to 10%. Fifth-wheel and gooseneck trailers carry a larger share. Change the lowest and highest share to match your manual.

## Sources

- Hyundai owner’s manual, If You Decide to Pull a Trailer: the tongue load measured at the hitch when fully loaded should be within 10–15% of the total weight of the trailer; never exceed the GVWR. https://ownersmanual.hyundai.com/full_webhelp/LX3/2026/en_US/topic_snf_hxj_x5b.html (retrieved 2026-10-18)
- Kia owner’s manual (KA4, 2024, US), If you do decide to pull a trailer: tongue weight at most 10% of the loaded trailer weight, and within the vehicle’s maximum tongue load. https://ownersmanual.kia.com/full_webhelp/KA4/2024/en_US/topics/t00397.html (retrieved 2026-10-18)
- NSW Government, Towing a trailer or caravan: as a general rule, the vehicle should carry about 5 to 10% of the loaded trailer’s mass at the coupling. https://www.nsw.gov.au/driving-boating-and-transport/roads-safety-and-rules/vehicle-safety-and-compliance/towing-a-caravan (retrieved 2026-10-18)
- NIST SP 811 (2008), Appendix B: 1 lb = 0.45359237 kg exactly. https://www.nist.gov/pml/special-publication-811 (retrieved 2026-10-18)