Caravan Payload Calculator
Check how much payload is left in your caravan against its ATM.
Result
432 kg payload remaining
- Payload capacity (ATM − Tare)
- 850 kg
- Water (1 litre = 1 kg)
- 150 kg
- Total loaded
- 418 kg
- Remaining
- 432 kg
Payload capacity is your ATM minus tare weight. Weigh your loaded van at a public weighbridge to confirm.
How it's calculated
- Payload capacity = ATM − tare weight.
- Add up what you carry: water (1 litre = 1 kg), gas bottles, and gear, food and accessories.
- Payload remaining = payload capacity − what you carry. A negative number means you are over your ATM.
Worked examples
Using the default figures
ATM 3,500 kg − tare 2,650 kg = 850 kg of payload capacity. Carrying 150 L of water (150 kg), 18 kg of gas and 250 kg of gear is 418 kg in total, so 850 − 418 = 432 kg of payload remaining.
Terms explained
- ATM (Aggregate Trailer Mass)
- The most the caravan may weigh when fully loaded and not coupled to a tow vehicle. It is stated on the caravan's compliance plate.
- Tare weight
- The weight of the empty caravan as built, before you add water, gas, food and gear. Check the compliance plate or your build paperwork.
- Payload
- ATM minus tare weight: the weight you can add to the caravan before reaching its ATM.
- Tow-ball download
- The downward force the caravan's coupling puts on the tow vehicle's tow ball. It is part of the caravan's loaded weight and counts towards the tow vehicle's GVM.
Assumptions and notes
- Water is counted at 1 kg per litre.
- ATM and Tare must be taken from your caravan compliance plate — figures vary by build and options.
- Accessories fitted after manufacture (solar, batteries, bull bar, awning) reduce your payload.
- Results are estimates only and are not financial, tax or legal advice.
Information last checked: August 2026.
Frequently asked questions
What is ATM?
Aggregate Trailer Mass is the maximum total weight of the caravan when fully loaded and not coupled to a tow vehicle, as stated on the compliance plate.
Is payload the same as GTM?
No. GTM is the weight carried by the caravan's axles when coupled. Payload is the difference between ATM and tare weight.
What counts against my caravan's payload?
Everything you add after the van is built: water (1 kg per litre), gas bottles, food, clothes, gear, and accessories fitted later such as solar panels, batteries and awnings.
How do I check my loaded caravan weight?
Take the van, loaded as you would travel, to a public weighbridge and compare the figure with the ATM on the compliance plate.