Camping Propane Runtime Calculator
Enter your actual propane weight, appliance BTU ratings, daily burner time, and reserve. The calculator estimates daily propane use, runtime, trip fuel margin, and how much propane to start with.
Estimated runtime9.64
- Estimated propane use per day
- 1.76
- Usable propane after reserve
- 17
- Starting propane required for the trip
- 14.52
- Equivalent 1 lb bottles
- 15
- Trip fuel margin
- 4.66
- Largest propane use
- Heater (27000 BTU/day)
Appliance propane use
| Appliance | Input | Hours/day | BTU/day | lb/day |
|---|---|---|---|---|
| Heater | 9,000 | 3 | 27,000 | 1.25 |
| Stove or grill | 10,000 | 0.5 | 5,000 | 0.23 |
| Other equipment | 1,500 | 4 | 6,000 | 0.28 |
Uses 21548 BTU per pound of propane and treats entered burner time as actual flame-on time.
How to use this calculator
- Enter the net pounds of propane available before setting aside a reserve.
- Enter each appliance input rating in BTU per hour and the actual burner-on time per day.
- Use the other equipment row for a lantern, refrigerator, water heater, or similar propane load.
- Enter the planned trip length to compare your usable supply with expected trip consumption.
How the propane runtime is calculated
Propane appliances are usually rated by input, in BTU per hour. Runtime depends on that input rating, how long the burner is actually on, and how much of the starting propane you are willing to use before reaching your reserve. A heater controlled by a thermostat should use burner-on time, not the whole night that the heater is available.
The calculator uses 21,548 BTU per pound of propane. For each appliance row, daily energy is:
daily BTU = rated input BTU/h × burner hours per day
Then the rows are added together:
daily propane lb = total daily BTU ÷ 21,548
The reserve is held back from the starting supply:
usable propane = starting propane × (1 − reserve percent ÷ 100)
Estimated runtime is the usable propane divided by daily propane use. For trip planning, the same formula is reversed:
starting propane required = (daily propane lb × trip days) ÷ (1 − reserve fraction)
What moves the answer most
The largest driver is daily BTU, not the cylinder size printed on the collar. A 20 lb cylinder can last a long time with a small stove used briefly, but a furnace running for many burner-hours can use the same propane quickly. The appliance table shows BTU per day for each group so you can spot whether heat, cooking, or another load is setting the trip plan.
Reserve also matters. A 15% reserve means only 85% of the entered fuel is treated as usable. Raising the reserve lowers runtime and increases the starting propane required for the same trip.
What this estimate leaves out
The math assumes rated propane input and proportional burner time. Real use can change with wind, cold weather, altitude, regulator performance, appliance condition, partial-power operation, and how often a thermostat cycles. The result is a planning estimate, not a safety approval for any cylinder, appliance, tent, cabin, or RV installation.
Worked example
Suppose you start with 20 lb of propane and keep a 15% reserve. A 9,000 BTU/h heater runs 3 burner-hours per day, a 10,000 BTU/h stove runs 0.5 hours per day, and other propane equipment uses 1,500 BTU/h for 4 hours per day.
The daily energy is 27,000 + 5,000 + 6,000 = 38,000 BTU. Dividing by 21,548 gives about 1.76 lb of propane per day. After reserve, 20 lb leaves 17.00 lb usable, so estimated runtime is about 9.64 days. For a 7-day trip, expected use is about 12.34 lb, starting propane required is about 14.52 lb, the equivalent bottle count is 15 one-pound bottles, and the trip margin is about 4.66 lb.
Common questions
How long will a 20 lb propane tank last while camping?
It depends on the appliance ratings and burner time. A continuous 30,000 BTU/h furnace can use a 20 lb cylinder in less than a day, while a stove used for short cooking periods may last many days. Enter the actual BTU ratings and daily burner time for your setup.
How do I find an appliance's BTU-per-hour rating?
Look for the input rating on the appliance data plate, manual, or manufacturer specification sheet. For a stove or grill, add the burners that are normally on at the same time. Use input BTU/h rather than heat output when both are listed.
Should thermostat-off time count as heater runtime?
No. Enter the time the burner is actually firing. If a heater is available for eight hours but cycles on for roughly three total hours, use three hours per day.
How much propane should I reserve?
A reserve is a planning buffer for weather, colder nights, cooking changes, and measurement error. Many campers keep some fuel back instead of planning to run a cylinder empty. This calculator lets you choose the reserve, but it does not decide what is safe or required for your trip.
Does a 20 lb cylinder contain 20 lb of propane?
A standard 20 lb cylinder is named for its propane capacity, not its total scale weight. The filled cylinder weighs more because the metal cylinder has its own tare weight. Enter the net propane available, not the full cylinder weight on a scale.