Propane Grill Calculator
Calculate how many 20-lb propane tanks you need per grilling season from BTU rating, burners, and weekly hours.
Returns hours per tank and yearly cost.
BBQ grill propane usage depends on the grill’s BTU output, how many burners you use, and how long you cook. Knowing your consumption rate helps you avoid running out mid-cookout and plan refills or tank swaps.
Formulas: BTU Consumption Rate = Number of Burners × Burner BTU Rating × Fraction of Max Setting Propane Used (gallons) = BTU Consumed ÷ 91,452 BTU/gallon Propane Used (lbs) = BTU Consumed ÷ 21,548 BTU/lb Cook Time Available = Remaining Propane (BTU) ÷ BTU Consumption Rate Cost per Grilling Session = Propane Used (gallons) × Price per Gallon
Propane energy content:
- 1 gallon of liquid propane = 91,452 BTU
- 1 lb of propane = 21,548 BTU
- A standard 20-lb tank holds approximately 4.7 gallons
- A full 20-lb tank contains approximately 430,000 BTU
Typical gas grill BTU ratings:
| Grill Size | Burners | Total BTU |
|---|---|---|
| Small 2-burner | 2 | 20,000–30,000 BTU |
| Mid-size 3-burner | 3 | 30,000–40,000 BTU |
| Large 4-burner | 4 | 40,000–60,000 BTU |
| Professional 6-burner | 6 | 60,000–90,000 BTU |
Actual cooking often uses 50–70% of maximum BTU (medium heat for most grilling).
Worked example: 3-burner grill rated at 36,000 BTU total (12,000 BTU/burner). You grill for 2 hours using all 3 burners at medium heat (60% output).
BTU used = 36,000 × 0.60 × 2 = 43,200 BTU Propane used = 43,200 ÷ 91,452 = 0.47 gallons Propane by weight = 0.47 × 4.24 lbs/gal = 2.0 lbs Cost at $3.00/gallon = 0.47 × $3.00 = $1.41 per session
How long does a 20-lb tank last? Total BTU in tank = 430,000 BTU At 43,200 BTU per 2-hour session: Sessions = 430,000 ÷ 43,200 = ~10 sessions (about 20 hours of cooking)
Checking tank level without a gauge: Pour warm water down the side of the tank. Feel for where it changes from warm to cool — the cool line is where the liquid propane level is. Weigh the tank: subtract the tare weight (stamped “TW” on the collar, usually 17–18 lbs) from total weight to get propane remaining.