Propane BTU Converter
Convert between propane gallons, BTU, kWh, and therms.
Calculate energy content of propane for heating and appliance sizing.
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Propane (liquefied petroleum gas / LPG) is a common fuel for heating, cooking, and power generation. Understanding its energy content helps compare costs with other fuels and size appliances correctly.
Core conversion factors for propane:
- 1 gallon of propane = 91,502 BTU
- 1 gallon of propane = 26.82 kWh
- 1 gallon of propane = 0.915 therms
- 1 gallon of propane weighs approximately 4.2 lbs (1.9 kg)
Other useful propane conversions:
- 1 therm = 100,000 BTU
- 1 kWh = 3,412 BTU
- 1 cubic foot of propane gas = 2,516 BTU
- 1 gallon of propane = 36.39 cubic feet of gas
Propane vs other fuels energy comparison:
| Fuel | Energy per Unit | Equivalent to 1 Gallon Propane |
|---|---|---|
| Natural gas | 1,030 BTU/cu ft | 88.8 cubic feet |
| Heating oil | 138,500 BTU/gal | 0.66 gallons |
| Electricity | 3,412 BTU/kWh | 26.8 kWh |
| Wood (cord) | 20,000,000 BTU/cord | 0.0046 cord |
| Kerosene | 135,000 BTU/gal | 0.68 gallons |
Common propane tank sizes:
| Tank Size | Gallons (full at 80%) | BTU Capacity |
|---|---|---|
| 20 lb (BBQ tank) | 4.7 | 430,059 |
| 100 lb | 23.6 | 2,159,447 |
| 120 gallon | 96 | 8,784,192 |
| 250 gallon | 200 | 18,300,400 |
| 500 gallon | 400 | 36,600,800 |
| 1,000 gallon | 800 | 73,201,600 |
Note: Propane tanks should only be filled to 80% capacity to allow for thermal expansion of the liquid.
Propane appliance consumption estimates:
- Furnace (100,000 BTU): approximately 1.09 gallons per hour
- Water heater (40,000 BTU): approximately 0.44 gallons per hour
- Gas range/oven: approximately 0.04 gallons per hour per burner
- Gas fireplace (25,000 BTU): approximately 0.27 gallons per hour
- Gas dryer: approximately 0.05 gallons per load
Practical tip for cost comparison: To compare propane vs electricity cost, divide the price per gallon of propane by 26.82 to get the equivalent cost per kWh. If electricity costs more per kWh than that result, propane is cheaper for heating.