There’s nothing quite like the warm, inviting glow of a fire pit on a cool evening. It’s the perfect centerpiece for gathering with friends and family, sharing stories, and simply relaxing. But if you’re new to the world of gas fire pits, one question inevitably pops up as you’re planning your evening: just how long does a propane tank last on a fire pit? Knowing the answer is the key to avoiding a mid-conversation flame-out and ensuring your cozy ambiance lasts all night long.
Figuring out the exact runtime isn’t as simple as checking a clock. It depends on a few important factors that we’ll walk through together. By the end of this article, you’ll have a clear and practical answer to the question, How Long Does a Propane Tank Last on a Fire Pit? – Here’s the Answer [Upd. 2025], and you’ll be able to plan your next backyard gathering with complete confidence.
How Long Does a Propane Tank Last on a Fire Pit? – Here’s the Answer [Upd. 2025]
Let’s get straight to the heart of the matter. For a standard 20-pound propane tank (the kind you typically use for a grill or fire pit) and a medium-sized fire pit running at a moderate flame height, you can generally expect a burn time of approximately 8 to 12 hours. This is a great starting point, but it’s an average. Your actual experience could be shorter or longer, and it all comes down to a few key variables that you have direct control over.
The Main Factors That Affect Your Burn Time
Think of your propane tank like the gas tank in your car. How long it lasts depends on how hard you’re pushing the engine. The same principle applies to your fire pit. Here are the main elements that influence your propane consumption.
Your Fire Pit’s BTU Rating
BTU, or British Thermal Unit, is a measure of energy output. It tells you how much heat your fire pit generates per hour. You can usually find the BTU rating on a sticker on the fire pit itself or in the owner’s manual. A higher BTU means a more powerful flame and faster fuel consumption. A fire pit with a 50,000 BTU rating will use propane much more quickly than one rated at 30,000 BTU, all else being equal.
Your Flame Height Setting
This is the single biggest factor you control every time you use your fire pit. It’s simple: the higher you turn the flame, the more gas flows, and the faster your tank will empty. Running your fire pit on a low, gentle setting for ambiance will extend your tank life significantly compared to blasting it on high to generate maximum heat.
The Size of Your Propane Tank
While the 20-lb tank is the standard, it’s not the only option. Some smaller, portable fire pits are designed to work with 1-lb disposable cylinders, which may only last for a few hours. On the other hand, if you have a permanent fire pit connected to a larger, 100-lb tank or even a home propane system, your runtime will be dramatically longer.
A Simple Calculation to Estimate Your Runtime
If you want a more personalized estimate, there’s a straightforward formula you can use. It all starts with knowing your fire pit’s BTU rating.
A standard 20-lb propane tank holds about 4.7 gallons of propane when full. One gallon of propane contains roughly 91,500 BTUs of energy. This means a full 20-lb tank holds approximately 430,000 BTUs in total (4.7 gallons x 91,500 BTUs).
To find your estimated burn time, you simply divide the total BTUs in the tank by your fire pit’s BTU rating:
Total Tank BTUs (430,000) ÷ Fire Pit BTU Rating = Estimated Hours of Burn Time
Example: If your fire pit has a rating of 40,000 BTUs, the math would be: 430,000 ÷ 40,000 = 10.75 hours. This means you could expect about 10 to 11 hours of burn time at the maximum flame setting.
Smart Tips to Make Your Propane Last Longer
Want to get the most out of every tank? A few simple habits can help you extend those cozy evenings.
- Embrace the Low Flame: You don’t always need a roaring inferno. For most social gatherings, a medium or low flame provides plenty of warmth and a beautiful atmosphere while conserving a great deal of fuel.
- Use a Wind Guard: If your fire pit is in a windy spot, a lot of heat is being blown away, forcing you to turn up the flame to compensate. A simple wind guard can block the breeze, making your fire pit more efficient and comfortable.
- Keep a Spare Tank: This is the golden rule of propane grilling and fire pits. Always have a full, backup tank on hand. This way, when one tank runs out, you can quickly and easily swap it out without interrupting the mood.
- Check for Leaks: Before you connect a new tank, do a quick safety check. Apply a soapy water solution to the connection hose and regulator. If you see bubbles forming, you have a leak that needs to be addressed before use.
Is Your Tank Empty? How to Tell for Sure
It’s frustrating to be left guessing. The easiest way to check your propane level is to pour a cup of hot water down the side of the tank. Feel the metal side with your hand immediately afterward. You’ll feel a distinct temperature change: the tank will be warm to the touch down to the level of the propane inside, and cool where the tank is empty. This simple trick gives you a clear visual and tactile gauge of how much fuel you have left.
In the end, a standard propane tank should give you many enjoyable evenings around the fire. By understanding the factors at play, especially your flame setting, you can effectively manage your fuel and ensure the good times—and the warm flames—keep going strong.