How much grilling is left in your tank? Set your tank, fuel level, and grill BTUs — the answer updates instantly, with the math shown.
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A standard exchange / "20 lb" tank holds about 20 lb of propane (~432,000 BTU) when full.
No gauge? Use the warm-water trick below, or switch to "Weigh the tank" for a precise number.
Put the tank on a bathroom scale. Subtract the TW stamped on the collar (~17.2 lb on most 20 lb tanks). Remaining propane = current − tare.
Add up every burner (and side / sear burners if lit). Check the label under the lid or the manual.
Used to estimate "how many more cookouts" you have left.
Grilling time left
of grilling left
hours = (lb propane × 21,594 BTU/lb) ÷ grill BTU/hr
Propane is just stored energy, and that energy burns at a known rate. Once you know how much fuel is in the tank and how fast your grill burns it, the math is simple and exact.
Two numbers drive everything:
Say you have a 20 lb tank that is about half full, feeding a three-burner grill rated at 40,000 BTU/hr.
Propane left: 20 lb × 0.50 = 10 lb
Energy left: 10 lb × 21,594 = 215,940 BTU
Run time: 215,940 ÷ 40,000 = 5.4 hours — about 5 hr 24 min of grilling, or roughly five 1-hour cookouts.
That is exactly what the calculator above does. It is an estimate of full-throttle run time: if you grill on medium or low, a lot of the time you will get more than this, because most cooks do not run every burner on high the whole time.
Stand the tank on a bathroom scale. Subtract the tare weight (the "TW" number stamped on the handle collar — usually near 17.2 lb). The difference is pounds of propane left. Use "Weigh the tank" mode above for an exact answer.
Pour warm (not boiling) water down one side of the tank, then run your hand down the metal. It feels cool below the propane line because the liquid absorbs heat. That shows the level, though not the exact pounds.
An inline pressure gauge or a dedicated propane tank scale gives a quick read. Pressure gauges are temperature-sensitive, so a scale is the reliable way to know what is really in there.
A few inexpensive tools take the guesswork out of "do I have enough propane?":
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A full 20 lb tank holds about 432,000 BTU. On a 30,000 BTU/hr grill that is roughly 14 hours; on 40,000 BTU/hr about 10–11 hours; on 60,000 BTU/hr about 7 hours — at full output. Most people grill on medium for an hour or two at a time, so a tank commonly lasts 8–20 cookouts.
It is the time if every burner you counted runs at its full rated output the whole time — a conservative, "worst case" number. Cooking on medium or low, you will usually get noticeably more grilling than the estimate shows.
Look for a rating plate under the lid, on the firebox, or in the manual, and add up every burner. As a rough guide: two-burner grills are often 26,000–30,000 BTU/hr, three-burner 36,000–45,000, and larger grills 50,000–75,000. Use the closest preset above if you are unsure.
Weighing is the only way to know the exact amount of propane left. Subtract the tare weight (TW) stamped on the collar from the tank's current weight on a scale, and you have the pounds of gas remaining — no guessing at a percentage.