Tow-Ball Weight Calculator
Estimate tow-ball download as a percentage of your loaded caravan weight.
Result
320 kg target tow-ball weight
- Target download
- 320 kg
How it's calculated
- Target tow-ball weight = loaded caravan weight × target percentage ÷ 100.
- If you enter a measured tow-ball weight, the calculator shows it as a percentage of the loaded caravan weight so you can compare it with your target.
Worked examples
A 3,200 kg loaded caravan at 10%
3,200 × 10 ÷ 100 = 320 kg target tow-ball weight. If tow-ball scales read 280 kg, that is 280 ÷ 3,200 = 8.75%, which is below the 10% target.
Terms explained
- Tow-ball download
- Also called tow-ball weight: the downward force the caravan or trailer's coupling puts on the tow vehicle's tow ball.
- ATM (Aggregate Trailer Mass)
- The most the caravan or trailer may weigh when fully loaded and not coupled to a tow vehicle, as shown on its compliance plate. This page uses your loaded weight in the same box.
Assumptions and notes
- Tow-ball download is commonly quoted around 10% of loaded trailer weight, but always follow the caravan and tow vehicle manufacturer specifications.
- Measure with tow-ball scales on level ground at coupling height.
- Results are estimates only and are not financial, tax or legal advice.
Information last checked: August 2026.
Frequently asked questions
How much tow-ball weight should a caravan have?
It is commonly quoted at around 10% of the loaded caravan weight, but the caravan and tow vehicle manufacturers set the limits that apply to you. Check both before you rely on a percentage.
Does tow-ball weight count towards my car's GVM?
Yes. The tow vehicle carries the download, so it is added to the vehicle's loaded weight when you check GVM. The towing capacity calculator does this for you.
How do I measure tow-ball weight?
Use tow-ball scales on level ground with the caravan loaded as you would travel and the coupling at towing height.