Propane Gas Grill Calculator

Look at the metal collar at the top of your propane tank — you'll see 'TW' stamped followed by a number in pounds. This is the tare weight, or the weight of the tank when completely empty. For a standard 20 lb BBQ tank, this is typically 16.6 lbs, though it can vary slightly by manufacturer.

BTU stands for British Thermal Unit — it's the measure of heat energy your grill can produce per hour. A higher BTU rating means your grill can generate more heat, but it also burns through propane faster. For most backyard grills, a total BTU rating between 20,000 and 60,000 is common, and cooking surface area matters just as much as raw BTU output.

For a standard 2–4 burner backyard grill, 25,000–50,000 total BTUs is plenty for most cooks. A good rule of thumb is roughly 80–100 BTUs per square inch of cooking surface. More burners and a larger cooking area generally warrant a higher BTU rating, but an efficient grill with good heat retention can outperform a higher-BTU model.

Propane contains about 91,502 BTUs per gallon and weighs approximately 4.2 lbs per gallon. A grill burning at 32,000 BTU/hr consumes roughly 0.35 gallons (about 1.47 lbs) per hour at full throttle. Running fewer burners or lower heat significantly reduces consumption.

A full 20 lb propane tank holds approximately 4.7 gallons of propane. At a typical consumption rate of 32,000 BTU/hr using all burners, it will last roughly 13–14 hours. With only half the burners running, you could expect 25–28 hours of total grill time from the same tank.

Propane tanks are typically filled to 80% of their total capacity as a safety measure — this allows room for the gas to expand with temperature changes. So a '20 lb tank' holds 20 lbs of propane when filled to the safe level, but the total weight includes the tare weight of the tank shell itself.

Propane offers convenience and portability that charcoal and natural gas can't match — you can take it anywhere. It lights instantly, heats quickly, and is easy to control. Compared to natural gas, propane burns slightly hotter (more BTUs per cubic foot) and doesn't require a fixed gas line, making it the most flexible fuel choice for most backyard cooks.

The calculator gives a solid estimate based on your tank weights, BTU rating, and number of active burners. Real-world usage can vary slightly due to ambient temperature (cold weather reduces tank pressure), heat setting, and wind. For the most accurate results, weigh your tank with a reliable scale and use the actual tare weight stamped on the collar.