Trailer Tongue Weight Calculator
Calculate ideal trailer tongue weight as a percentage of gross trailer weight to check safe towing balance, free right in your browser.
Enter Values
How to use this calculator
- Enter the loaded trailer weight and the measured tow-ball weight.
- Read the percentage and the guidance.
How it works
Tow-ball weight ÷ trailer weight × 100. A common target is around 10% (typically 9–11%).
Worked example
150 kg ball, 1500 kg trailer. = 10% — in the ideal range.
Common mistakes
- Too little ball weight causes dangerous trailer sway.
- Exceeding the vehicle's or tow-bar's rated tow-ball download.
Frequently asked questions
What should tongue weight be?
Usually about 10% of the loaded trailer weight (a little higher for some setups). Too little causes sway; too much overloads the rear axle.
How do I adjust tongue weight?
Shift load over the axle — moving cargo ahead of the axle raises tongue weight, behind it lowers it. Never exceed your tow ball's rating.
What tow-ball percentage is safe?
Around 10% is the usual aim, within roughly 9–11% — but always stay within your vehicle and tow-bar ratings.
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Cite this tool
Zerdly. (2026). Trailer Tongue Weight Calculator. Retrieved from https://www.zerdly.com/tools/trailer-tongue-weight-calculator/
Tip: Enter any known values to calculate the remaining results.
Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.