Propane Usage Calculator
This tool uses the input rating on each appliance instead of a general household average. Enter the BTU/h rating and daily burner time for each appliance. The result compares propane use with the gallons between an 80% fill and your refill level.
1Heating and hot water
Enter the input rating from each appliance label. Then enter how long its burner runs on an average day.
2Cooking, laundry, and backup
Propane tanks are normally filled to about 80% of their listed water capacity.
Use your supplier's delivery or reserve level. The common 20% setting leaves a 20% tank reserve.
Estimated propane use
132.9 gallons/month
4.37 gallons for one day with the run times entered above.
Yearly estimate
1,593 gal/year
Use this only if the entered day is typical for the whole year.
Gallons at 80% fill
400 gal
Gallons before refill
300 gal
100 gallons remain at the entered reserve level.
Days until refill
68.7 days
The tool multiplies the appliance input rating by burner hours. Actual use can change with thermostat cycling, weather, standby loss, changing burner output, generator load, and how fast the tank makes propane vapor.
Inputs stay in this browser. No account or quote request is required.
Quick planning answer
One gallon of propane contains about 91,452 BTU. An 80,000 BTU/h furnace that burns for four hours uses about 3.5 gallons. Your water heater, range, dryer, fireplace, and generator can add more.
Use the input rating on the appliance label
Enter input BTU/h, not heating output. The burner uses the input amount of fuel. Efficiency tells you how much of that fuel becomes useful heat. Modulating equipment often runs below its highest rating, so using full input for every burner hour gives a cautious estimate.
Generator fuel use changes a lot with electrical load. If the manual lists fuel use at 25%, 50%, and full load, use that table instead of the simple BTU rating.
Do not use one weather day for the whole year
Four furnace hours may make sense on a cold day. It does not make sense in July. Model a cold month, a mild month, and a summer month separately. Then compare those results with delivery records or local heating degree days.
- Write down the tank level before and after a known week.
- Record gallons delivered, outdoor temperature, and generator or fireplace use.
- Watch for a sudden increase that continues after the weather warms. Ask for service or a leak check.
- Never use a flame or a homemade test to look for a propane leak. If you smell gas, leave the area and follow your supplier's emergency steps.
Tank volume is not the only limit
A 500-gallon tank normally holds about 400 gallons when filled to 80%. In cold weather, several large burners may need propane vapor faster than the tank can make it, even when liquid remains. Your supplier should size the tank, regulators, and pipes for the connected appliances and local climate.
Use days per fill to help plan deliveries. Keep the reserve level required by your supplier. If the tank runs empty, air can enter the system and a leak check may be required before service starts again.
Questions people ask before buying
How many BTU are in a gallon of propane?
A common planning value is about 91,452 BTU per gallon. Divide the total appliance input used by 91,452 to find the estimated gallons.
How much propane does an 80,000 BTU furnace use?
At full input, it uses about 0.875 gallon for each burner hour. A furnace that cycles or lowers its output may use less. Track burner time or deliveries for a closer number.
Why can a propane tank only be filled to 80%?
The empty space lets liquid propane expand when its temperature changes. That is why a tank's listed water capacity is larger than the propane delivered during a normal full fill.
Can this calculator predict winter deliveries?
It can turn an appliance schedule into estimated gallons. To plan deliveries, you also need past delivery records, thermostat run time, weather, home heat loss, generator use, and your supplier's reserve rules.
Method, sources and limits
For each appliance, the tool multiplies input BTU/h by daily burner hours. It adds all six appliance totals and divides by 91,452 BTU per gallon. The monthly estimate uses 30.4375 days. The yearly estimate uses 365 days.
The tool treats 80% of the tank's water capacity as the filled level, subtracts the refill percentage you enter, and divides the remaining gallons by daily use to find days until refill. The result does not include changing burner output, weather, regulator limits, or how fast the tank can make vapor.
- Propane energy conversion factors (U.S. Energy Information Administration)
- Propane safety and energy basics (Propane Education & Research Council)
- What to do if you smell propane (Propane Education & Research Council)