Propane Cost Calculator
Calculate residential and commercial propane heating fuel costs, tank refill requirements, and cost per million BTU (MMBtu) based on gallons consumed.
Home Size & Climate Demand
Propane Fuel & Energy Calculation
Total Fuel Cost = Gallons Used × Price per Gallon | Total Energy (BTU) = Gallons × 91,500 BTU/Gal- Propane Energy Density: 1 US gallon of liquid propane delivers approximately 91,500 British Thermal Units (BTU).
- Tank Safety Fill Rule: Stationary propane tanks are filled to a maximum of 80% capacity to allow for liquid expansion.
- Cost per Million BTU (MMBtu): Standard metric to benchmark propane against heating oil, natural gas, and electric heat pumps.
Step-by-Step Worked Example
Calculation Steps:
How to Use This Calculator
Assumptions & Limitations
- Uses standard liquid propane energy density of 91,500 BTU per US gallon.
- Tank sizing adheres to the 80% liquid thermal expansion rule (NFPA 58).
Frequently Asked Questions
Why are residential propane tanks only filled to 80%?
Liquid propane expands significantly as ambient outdoor temperatures rise. Propane suppliers leave 20% empty vapor space in the tank as a federally mandated safety buffer to prevent overpressurization.
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