Propane Tank Runtime Calculator
Estimate propane runtime from tank size (20 lb, 100 lb, 500 gal), appliance BTU rating, and daily usage hours.
Returns run days and refill cost estimate.
Estimated Runtime
Propane consumption varies by appliance BTU rating and usage hours. This calculator converts tank capacity to usable energy and estimates how long a tank will last.
Key conversion:
1 gallon of propane = 91,452 BTU of energy
Burn Time (hours) = (Tank Gallons × 91,452) / Appliance BTU Rating
Common tank sizes:
| Tank Size | Actual Propane | Common Use |
|---|---|---|
| 1 lb (disposable) | 0.24 gal | Camp stove, lantern |
| 20 lb (standard BBQ) | 4.7 gal | Gas grill, patio heater |
| 33 lb (forklift) | 7.7 gal | Forklifts, construction |
| 100 lb | 23.6 gal | Home heating, generators |
| 500 gal | ~400 gal usable | Whole-home systems |
Note: Tanks are never filled 100% full — propane expands with heat, so tanks are filled to ~80% capacity for safety.
Worked example — BBQ grill:
- 20 lb tank = 4.7 gallons usable
- Medium gas grill: ~35,000 BTU/hour
- Burn time: (4.7 × 91,452) / 35,000 = 12.3 hours of grilling
Worked example — Patio heater:
- 20 lb tank = 4.7 gallons
- Patio heater: ~50,000 BTU/hour
- Burn time: (4.7 × 91,452) / 50,000 = 8.6 hours
Common appliance BTU ratings:
- Portable camp stove: 7,500–10,000 BTU/hr
- Standard gas grill: 25,000–60,000 BTU/hr
- Patio / tower heater: 40,000–50,000 BTU/hr
- Home furnace: 60,000–120,000 BTU/hr
- Pool / spa heater: 100,000–400,000 BTU/hr