How long will a gas bottle last?
Convert the gas you have into hours of use, then allow for the way you actually run your appliances.
Runtime in hours = gas remaining in kg × 1,000 ÷ consumption in g/h. For example, 6 kg at a constant 200 g/h gives 30 hours. This is an arithmetic estimate, not a promise of 30 hours in every caravan.
Start with gas remaining, not bottle size
A part-used 6 kg bottle does not still contain 6 kg. Use your bottle’s own tare and current weight in the Gas Bottle Calculator. If the marking is confusing, read empty and full bottle weight explained.
Read your appliance’s consumption figure
Use the gas consumption in the manual for your exact appliance and operating setting. A quoted maximum is different from average daily consumption. For example, Truma’s 2025 international catalogue lists 160 and 335 g/h for the two gas burner settings of the Combi 4 / 4 E. Check the model and manual: do not apply those figures to every Truma heater. Source: Truma technical catalogue.
Worked runtime table
The table assumes the stated quantity of gas is available and one constant total consumption rate. The 100, 200 and 400 g/h rates are illustrative scenarios, not specifications for a particular cooker or heater.
| Gas remaining | 100 g/h | 200 g/h | 400 g/h |
|---|---|---|---|
| 3 kg | 30 h | 15 h | 7.5 h |
| 6 kg | 60 h | 30 h | 15 h |
| 13 kg | 130 h | 65 h | 32.5 h |
Turn appliance use into a daily budget
For each appliance, multiply consumption by hours running. Then add the results. An illustrative cooker at 150 g/h for one hour uses 150 g; a heater averaging 200 g/h while running for five hours uses 1,000 g. Together that is 1,150 g, or 1.15 kg per day. A full 6 kg gas charge would cover about 6 ÷ 1.15 = 5.2 days before allowing a reserve or any other gas use.
Include hot water and any gas fridge. If appliances run simultaneously, add their consumption rates for the instantaneous total. If a fridge manual gives grams per 24 hours, treat that as a daily figure rather than multiplying it by 24 again.
Why real runtime changes
Thermostatic cycling, weather, insulation, hot-water demand and cooking habits change the daily budget. Heating output in kW is not automatically gas input in kW: use the manufacturer’s consumption figure rather than assuming perfect efficiency. Keep a reserve appropriate to your trip and check supplies before relying on a theoretical last hour.
Gas still in a bottle does not guarantee it can supply the appliance at the required rate in cold conditions. See propane versus butane. Heating controls, fans and pumps may also need electricity; check your leisure battery runtime.
Safe use comes before runtime
Never use a cooker or barbecue to heat a tent, awning or vehicle. Use appliances only in the environment they are designed for, keep required ventilation clear and follow their servicing instructions. A carbon monoxide alarm does not replace safe installation and ventilation. See the Camping and Caravanning Club’s safety guidance.
Reviewed 6 October 2026. Examples are calculations, not measurements of your equipment.