How to Use the Propane Tank Duration Calculator
If you cook or grill with a propane tank, knowing roughly when it'll run out helps you avoid getting caught mid-meal with an empty tank. This calculator takes your tank size (20 lb or 100 lb), your burner's output (low, medium, or high), and your average daily usage hours, then estimates your daily propane consumption and how many days the tank should last. It's based on propane's standard heating value of about 21,548 BTU per pound.
A higher-output burner and longer daily use both increase how much propane you burn each day, which shortens the tank's lifespan. If you only fire up the grill occasionally, a 20 lb tank — the standard size most backyard grills use — can last a while. Heavier users, like a patio heater running for hours or a whole-house propane range, often do better with a 100 lb tank to cut down on refill trips.
Actual results can vary based on cooking habits, how often you adjust the flame, and how full the tank actually was to start. Treat this as an estimate based on average usage patterns, and plan your refill or exchange with some buffer before you expect to run out.
Frequently Asked Questions
We multiply your burner's BTU/hr rating by daily usage hours to get daily propane use in pounds, using propane's heating value of about 21,548 BTU per pound, then divide the tank size by that daily use.
A 20 lb tank (the standard size for grills) suits light or occasional use, while a 100 lb tank is common for heavier use like a whole-house range or patio heater. Compare the estimated days to match your refill schedule.