How Long Does a Propane Tank Last When Grilling?

Nothing ruins a good cookout faster than an empty propane tank. Before using propane, it is recommended that you know how long your propane tank lasts or how long it takes before it needs another refill. This helps you avoid running out halfway through cooking.  

As the largest retailer of propane in the U.S., we’ve broken down the numbers to help you estimate how long your propane tank will last. We’ll walk through everything you need to know about your propane level to keep your grill running smoothly. 

How Long Does a Propane Tank Last? 

The exact burn time depends on your grill’s British Thermal Unit (BTU) rating, how many burners you’re using, and the size of your propane tank. Here’s a general idea of how long a full propane tank lasts when grilling on high heat: 

These estimates assume a full tank, average grill BTU output, and steady outdoor conditions. Actual results may vary depending on the type of propane appliance you’re using, your specific grill, and your cooking habits.  

What Affects Propane Burn Time? 

Several factors determine how long your propane tank will last. 

Tank size is the most obvious one. Larger tanks simply hold more fuel. A 40-lb tank will run longer than a 20-lb tank under the same conditions. 

Your grill’s BTU rating also plays a major role. BTUs measure heat output. The higher the BTU rating, the more propane your grill consumes per hour. 

How you cook matters too. Running all burners on high will drain propane much faster than using one or two burners on medium heat. Cold or windy weather can also increase fuel usage because the grill must work harder to maintain temperature.  

Here’s an in-depth look at average burn times broken down by grill size, tank size, and heat output: 

Grill Size	Burn Time on Low – for a 20-lb tank	Burn Time on Low – for a 30-lb tank	Burn Time on Low – for a 40-lb tank
3 Burner	27.91 hours	42.47 hours	55.81 hours
4 Burner	20.93 hours	31.85 hours	41.86 hours
5 Burner	16.74 hours	25.48 hours	33.49 hours
6 Burner	13.95 hours	21.23 hours	27.93 hours
Grill Size	Burn Time on Med – for a 20-lb tank	Burn Time on Med – 30-lb tank	Burn Time on Med – for a 40-lb tank
3 Burner	18.60 hours	28.31 hours	37.21 hours
4 Burner	13.95 hours	21.23	27.91 hours
5 Burner	11.16 hours	16.99 hours	22.33 hours
6 Burner	9.30 hours	14.16 hours	18.60 hours
Grill Size	Burn Time on High – for a 20-lb tank	Burn Time on High – 30-lb tank	Burn Time on High – for a 40-lb tank
3 Burner	13.95 hours	21.23 hours	27.91 hours
4 Burner	10.47 hours	15.93 hours	20.93 hours
5 Burner	8.3 hours	12.74 hours	16.74 hours
6 Burner	6.98 hours	10.62 hours	13.95 hours

How Do You Calculate Propane Burn Time? 

If your grill isn’t listed above, you can estimate burn time using a simple formula. This calculation assumes continuous use on high and full tanks. Standard 20-lb grill tanks typically hold about 20 pounds of propane when filled properly. 

Formula for calculating estimated propane burn time: 

(Propane tank size in pounds × ~21,000 BTUs per pound) ÷ Appliance BTU rating = Estimated burn time in hours 

The value of ~21,000 BTUs per pound is a simplified estimate used to help calculate propane burn time. For example, if you have a 20-lb tank and a grill rated at 30,000 BTUs, you can estimate the burn time like this:  

(20 × 21,000) ÷ 30,000 = about 14 hours on high heat. 

Keep in mind that this estimate assumes the grill is running continuously at full power. In real cooking situations, burners are often turned down or used intermittently, which can extend how long a tank lasts.  

How to Check Your Propane Level 

The easiest way to avoid interruptions is to check your tank before big gatherings and refill ahead of time. Many U-Haul locations offer propane refilling, which allows you to top off your tank and pay only for the propane you need. Ig your tank is already empty, or you prefer a faster option, some locations also offer propane tank exchange, where you can swap your empty tank for a filled one and get back grilling.  

You can use a compatible propane tank gauge to monitor fuel levels and avoid running out unexpectedly. Many gauges attach directly to the tank and give you a quick reading of how much propane remains.  

Another simple method is the warm water test. Pour warm water down the side of the tank and feel for a cool spot; that temperature change can indicate the propane level inside. If you want a more precise estimate, weigh the tank and subtract the tare weight (TW) stamped on the collar. The difference is the amount of propane remaining. If you grill often, you can also keep a backup tank on hand to provide peace of mind.  

U-Haul offers propane refills at 1200+ locations across the U.S. and Canada, and some locations also offer propane tank exchange for a quick replacement when your tank is empty. Availability may vary by location. Make sure to check if your location offers propane refill service.  

Don’t know where to have your propane refilled? Find a U-Haul propane refill location near you and start your reservation today.