Propane Usage Calculator
Turn an appliance BTU/hr rating or gallons per hour, duty cycle and hours of use into propane gallons and pounds per day, tank runtime and monthly cost.
Interactive calculator · Method PROPANE-USAGE-1.0 · Last reviewed: 2026-11-04
Calculate your scenario
Full-fire gallons per hour = input rating (BTU/hr) ÷ heat content per gallon, or the gallons per hour you enter.
Your inputs
Default worked example. Edit the inputs to calculate your scenario.
Default worked example
60,000 BTU/hr ÷ 91,500 BTU/gal = 0.655738 gal/hr × 50% × 24 h = 7.8689 gal/day; 400 usable gal ÷ 7.8689 gal/day = 50.83 days.
How to use the calculator
Read the input rating (BTU/hr) from the appliance nameplate or manual, or enter gallons per hour. Estimate the share of time the burner actually runs and the hours per day, then enter the tank size, the share you can use and your price per gallon.
What the result means
A 60,000 BTU/hr furnace burns about 0.656 gal/hr at full fire; running half the time all day it uses about 7.87 gal/day, so 400 usable gallons of a 500 gal tank last about 50.8 days, roughly $598.77 a month at $2.50/gal.
Formula and units
Full-fire gallons per hour = input rating (BTU/hr) ÷ heat content per gallon, or the gallons per hour you enter. Gallons per day = gal/hr × duty cycle × hours per day; pounds per day = gallons × lb/gal. Usable fuel = tank size × usable share. Runtime in operating hours = usable gallons ÷ (gal/hr × duty cycle); in days = usable gallons ÷ gallons per day. Monthly gallons = gallons per day × 30.4375 (365.25 ÷ 12); cost = monthly gallons × your price.
Worked examples
60,000 BTU/hr furnace at 50% duty on a 500 gal tank: Appliance input rating: 60000 BTU/hr; Fuel use at full fire (if entering gallons per hour): 0.66 gal/hr; Duty cycle (share of running time the burner is on): 50 %; Hours of operation per day: 24 h/day; Tank size (water capacity): 500 gal; Usable share of tank (example 80%): 80 %; Propane price per gallon (example): 2.5 $ per gal; Heat content per gallon (approx. 91,500 BTU, HHV): 91500 BTU/gal; Propane weight per gallon (approx. 4.24 lb): 4.24 lb/gal; Appliance rating entered as: btu.
Example result: Gallons per day: 7.8689 gal/day; Pounds per day: 33.3639 lb/day; Usable fuel runtime (operating hours): 1,220 h; Usable fuel runtime (days): 50.83 days; Monthly gallons: 239.51 gal; Monthly fuel cost: $598.77.
Generator at 0.5 gal/hr for 8 h/day on a 100 gal tank: Appliance input rating: 60000 BTU/hr; Fuel use at full fire (if entering gallons per hour): 0.5 gal/hr; Duty cycle (share of running time the burner is on): 100 %; Hours of operation per day: 8 h/day; Tank size (water capacity): 100 gal; Usable share of tank (example 80%): 80 %; Propane price per gallon (example): 3 $ per gal; Heat content per gallon (approx. 91,500 BTU, HHV): 91500 BTU/gal; Propane weight per gallon (approx. 4.24 lb): 4.24 lb/gal; Appliance rating entered as: gph.
Example result: Gallons per day: 4 gal/day; Pounds per day: 16.96 lb/day; Usable fuel runtime (operating hours): 160 h; Usable fuel runtime (days): 20 days; Monthly gallons: 121.75 gal; Monthly fuel cost: $365.25.
Limitations and common mistakes
A fuel-use estimate from a nameplate input rating, which is the maximum burn rate; real use depends on how often the appliance cycles, so the duty cycle is your estimate or measurement. About 91,500 BTU per gallon (higher heating value) and 4.24 lb per gallon are commonly published approximations and vary with temperature and fuel blend; both are editable. This does not size tanks, regulators, piping, vents or combustion air and says nothing about safe installation. Prices are your entries.
Treating the nameplate BTU/hr as continuous use. Heaters and furnaces cycle on and off, so a 100% duty cycle usually overstates daily use.
Sources and assumptions
Method PROPANE-USAGE-1.0; last formula review 2026-11-04. Sources and their supported claims. Calculation methodology.