How long will a 20 lb propane tank last on a grill?
With every burner on high, a 30,000 Btu-per-hour grill empties a full 20 lb tank in about 14.4 hours. Grills rarely run flat out, so most cooks get far more.
How to work it out
- 20 lb ÷ 4.23 lb per gallon = 4.73 gal × 91,452 Btu = 432,397 Btu
- 432,397 Btu ÷ (30,000 Btu/h) = 14.4 hours
A grill’s Btu rating — on the label or in the manual — is the total for all main burners at full. Side burners and searing stations add to it when they are on. This page uses a 30,000 Btu grill as the example.
Adjust for your project
More options: Full · Duty
- In hours and minutes
- 14 h 25 min
- Propane in gallons
- 4.73 gal
- Energy in the tank
- 432,397 Btu
- Propane used per hour
- 1.39 lb
The same appliance on other tank sizes
| Tank | Runtime | Propane in gallons | Energy in the tank |
|---|---|---|---|
| 1 lb | 0.7 hours | 0.24 gal | 21,620 Btu |
| 20 lb | 14.4 hours | 4.73 gal | 432,397 Btu |
| 30 lb | 21.6 hours | 7.09 gal | 648,596 Btu |
| 40 lb | 28.8 hours | 9.46 gal | 864,794 Btu |
| 100 lb | 72.1 hours | 23.64 gal | 2,161,986 Btu |
Grilling time per tank
- Burner settings matter most. On medium, with fewer burners lit, use drops a lot; set the share under More options. At half, the same tank gives about 29 hours of cooking.
- Count your cooks. At about 45 minutes of full-power grilling a night, 14.4 hours is roughly 19 cooks.
- Weigh it. The tare weight (TW) is stamped on the collar — a full 20 lb cylinder weighs about that plus 20 lb. Subtract to see what is left.
- Keep a spare. Running out mid-cook is a rite of passage; a second cylinder or a gauge avoids it.
The same tank on a heater is on how long a 20 lb propane tank lasts for heating, and on a dual-fuel generator on how long a generator runs on a 20 lb propane tank. For a bigger supply, see how long a 100 lb propane tank lasts.
Different size? Use the full Propane Tank Runtime Calculator.
What you’ll need
- Propane tank gaugeBudget price
Shows roughly how much is left so you are not guessing halfway through a cold night or a long outage.
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Frequently asked questions
How long will a 20 lb tank last on a grill at medium (half output)?
About 28.8 hours.
How long will a 20 lb tank last on a 45,000 Btu grill?
About 9.6 hours with every burner on high.
How long will a 1 lb propane cylinder last on a camp stove at 10,000 Btu?
About 2 h 10 min at full flame.
Other common sizes
- How long a 20 lb propane tank lasts for heating — 24 hours at 18,000 Btu/h
- How long a 100 lb propane tank lasts — 72 hours at 30,000 Btu/h
Sources
- U.S. Energy Information Administration — British thermal units (Btu) (opens in a new tab) — Heat content: gasoline 120,214 Btu/gal, diesel 137,381 Btu/gal, propane 91,452 Btu/gal; 1 kWh = 3,412 Btu.
- NIST Chemistry WebBook — Thermophysical properties of propane (saturated liquid) (opens in a new tab) — Liquid propane is about 31.6 lb/ft³ at 60 °F, which is 4.23 lb per US gallon (4.09 at 80 °F).
- U.S. Consumer Product Safety Commission — Portable Generator Hazards (Safety Alert 5123, 2021) (opens in a new tab) — Never run a generator indoors or in a garage, even with doors open; place it outside far from doors, windows and vents; CO alarms; never “backfeed” by plugging into a wall outlet.