Everyday
Propane Refill Days Calculator
Enter your tank size and gauge reading plus how much propane you use each day, and the page works out how many days you have until you should order, the date to order by, and how many gallons to ask for to reach a full 80% fill.
How it works
Behind the numbers
Gallons on hand come first. The gauge reads a percentage of the tank's capacity, so a 500 gallon tank at 40% holds 200 gallons. The same reading on a 1,000 gallon tank means 400 gallons, which is why the tank size matters as much as the needle position. The page also works out the gallons at your order trigger: at 20%, a 500 gallon tank still holds 100 gallons, and the gap between the two figures is what you have left to burn before you should call.
Daily use sets the clock. Enter gallons per day directly if you track deliveries, or enter your furnace rating and hours per day and the page converts with 91,500 BTU per gallon: a 60,000 BTU furnace running 8 hours uses about 5.3 gallons a day. Dividing the gallons above the trigger by daily use gives days until the order trigger, and dividing all gallons on hand by daily use gives days until empty. A winter factor lets you scale daily use up for a cold snap, since a furnace that runs twice as long burns twice as much.
The order date and the order size finish the plan. Adding days until the trigger to today's date gives the date to order by, with a margin for delivery scheduling in cold weather. The gallons to order bring the tank back to an 80% fill, the most a supplier will put in: a 500 gallon tank at 40% takes 200 gallons to reach 400. If the gauge is already at or below the trigger, the page says to order now, and below 5% it warns that a supplier generally needs a leak check before refilling a tank that has run that low.
FAQ
Questions, answered
When should I order propane?
Most suppliers recommend ordering when the gauge reaches 20 to 30%. That leaves a buffer for delivery scheduling and cold snaps. Waiting until the tank reads near empty risks running out, and a tank that drops below about 5% generally needs a leak check before it can be refilled.
Why does my propane gauge never read 100%?
Tanks are filled to about 80% of capacity to leave room for the liquid to expand as temperatures rise. A gauge reading 80% after a delivery means a full tank, and the same reading in percent of capacity is what this calculator uses.
How many gallons are in my tank at 40%?
Multiply the gauge reading by the tank's capacity: 40% of a 500 gallon tank is 200 gallons, and 40% of a 1,000 gallon tank is 400 gallons. The gauge reads a percentage, not gallons, so two tanks at the same reading can hold very different amounts.
How do I estimate daily propane use from my furnace?
Multiply the furnace rating in BTU per hour by the hours it runs each day, then divide by 91,500, the BTU content of a gallon of propane. A 60,000 BTU furnace running 8 hours a day uses about 5.3 gallons a day. In a cold snap the furnace runs longer, so raise the winter factor or the hours to match.
What size propane tanks do homes usually have?
Residential tanks are commonly 120, 250, 500 or 1,000 gallons. Check the capacity on the tank's data plate if yours is not listed, and enter that number: the gauge percentage only turns into gallons once the capacity is known.