Propane Calculator: How Long Will Your Propane Last?
Fuel is the one thing you cannot improvise at a campsite. This calculator answers the question that actually decides your packing list: given the canister or tank you own and the burner you are running it on, how many hours of cooking do you get, how many meals is that, and what does each hour cost you? The maths is the same one we use in our camp stove fuel guide, just worked through for your numbers.
$64.99 for a 12-pack of Coleman 16.4 oz cylinders = $5.42 each. Runtime assumes your full rated output only for the share of the time you are actually at high heat — a stove that is simmering burns far less than its rating. Cold weather, wind and altitude all cut real-world runtime, so treat these numbers as a planning ceiling rather than a promise.
How the propane calculator works
Every number comes from two facts about propane: it carries about 91,500 BTU per gallon, and a gallon weighs about 4.24 lb. Divide one by the other and you get roughly 21,500 BTU per pound of propane. A fuel container holds a known weight of propane, your stove burns a known number of BTU per hour, so hours of runtime is just energy divided by burn rate.
- A 1 lb canister (the familiar 16.4 oz green cylinder) holds one pound of propane, so about 21,500 BTU.
- A 20 lb BBQ tank is filled to roughly 4.6 gallons, which is about 19.5 lb of propane and around 430,000 BTU.
- A 110 g isobutane canister holds about a quarter of a pound — roughly 5,200 BTU, which is why backpackers count boils rather than hours.
The second half of the calculation is the one people get wrong. A stove rated at 10,000 BTU per hour only burns 10,000 BTU per hour while it is turned all the way up. Soup that simmers for twenty minutes is not consuming full output for twenty minutes, so the calculator applies a duty factor based on how you cook — which is why the “hours of real cooking” figure is always longer than the flat full-blast number.
Propane runtime reference table
| Fuel container | Net propane | Energy | 8,000 BTU/hr | 10,000 BTU/hr | 22,000 BTU/hr |
|---|---|---|---|---|---|
| 1 lb canister (16.4 oz cylinder) | 1 lb | ~21,500 BTU | 2.7 hrs | 2.2 hrs | 1.0 hrs |
| 110 g isobutane canister | 0.24 lb | ~5,200 BTU | 0.7 hrs | 0.5 hrs | 0.2 hrs |
| 5 lb refillable tank | 5 lb | ~107,500 BTU | 13.4 hrs | 10.8 hrs | 4.9 hrs |
| 20 lb BBQ tank (full refill) | ~19.5 lb | ~430,000 BTU | 53.8 hrs | 43.0 hrs | 19.5 hrs |
The 22,000 BTU column is the realistic figure for a two-burner family stove with both burners going, which is why a one-pound canister that feels generous on a single burner feels short when you are cooking for four.
What actually changes the answer on a real trip
Published ratings assume a warm, still day at sea level. None of those conditions are guaranteed at a campsite, and three of them bite hard:
- Wind. A pot sitting in a breeze loses heat as fast as the burner adds it, and that wastes gas. Sheltering the stove — a windscreen, a windbreak of rocks, the tailgate of the car — is the single cheapest way to stretch a canister. It is also why bottle-top burners with an integrated shield hold their rated output far better than a bare burner.
- Cold. Straight propane boils at about minus 44 F, so a 1 lb propane cylinder or a 20 lb tank keeps delivering in winter. Isobutane boils near 11 F and its output falls away well before that, which is the whole reason isobutane and propane behave differently in a canister stove. Sleeping with the canister, or keeping it in an inside pocket, really does restore pressure.
- Altitude. Lower air pressure means water boils at a lower temperature and takes longer to get there, so every meal costs more fuel the higher you camp. Above about 6,500 ft, add a full spare canister to whatever the calculator suggests.
One more rule from experience: subtract nothing, then add a spare. A canister that is “probably enough” always runs dry during the one meal when everyone is hungry, and there is no topping up a propane cylinder at a trailhead.
1 lb canisters vs a 20 lb tank: the cost picture
This is the calculation that surprises people. Per unit of heat, small canisters cost about five times as much as bulk propane:
- 1 lb canisters. A 12-pack of 16.4 oz cylinders is around $64.99, or about $5.42 each. Because each can holds roughly 21,500 BTU, that works out near $25 per 100,000 BTU.
- 20 lb tank. A refill runs about $21 and contains roughly 430,000 BTU — under $5 per 100,000 BTU.
- Refilling your own 1 lb cylinders. A refillable cylinder plus a refill adapter lets you fill small cans from a big tank, which keeps one-pound convenience while dropping the per-BTU cost toward bulk prices. It is the single biggest fuel saving available to a car camper, and it is what makes short trips cheap instead of convenient but expensive.
The practical split most families land on: a twelve-pack of one-pound cylinders for short trips, day hikes and emergencies, and a two-burner stove on a hose and a 20 lb tank for anything longer than a weekend.
The gear that matches these numbers
If the calculator says you need more burn time, there are only four honest ways to get it: bigger fuel, more efficient burner, better shelter from wind, or lower expectations.
- Fewer BTU per hour. A bottle-top single burner rated 10,000 BTU will run twice as long on the same canister as a high-output two-burner. For coffee and one-pot meals, that efficiency is the whole game.
- Backpacking efficiency. A PocketRocket 2 paired with a 110 g isobutane canister is the lightest possible version of this: two people, hot meals, about a pound of pack weight.
- Bulk fuel for basecamp. The Camp Chef Explorer two-burner burns more per hour than anything else here, so it belongs on a 20 lb tank rather than a canister. Pair it with an 20 lb to 1 lb converter if you want to run a small lantern or single burner off the same tank.
- Cold-weather heat. A Buddy-style radiant heater empties a one-pound canister in about two and a half hours on high, which is the number to plan around for a shoulder-season weekend.
- Refill instead of rebuy. A refillable 1 lb cylinder and kit plus a 1 lb to 20 lb refill adapter turns a 20 lb tank into twelve small cans for the price of one refill.
Safety note, because it matters more than runtime: propane belongs outside. Do not run a camp stove, a grill or a radiant heater inside a tent, and check hose connections for leaks before the first meal of every trip, not just the first trip of the season.
Propane Calculator FAQ
How long does a 1 lb propane tank last?
About 2 hours and 10 minutes on a 10,000 BTU single burner running at full blast, because a 1 lb cylinder holds roughly 21,500 BTU. Most families get three to four meals out of one canister in practice, since a stove spends much of its time simmering rather than at full output. A Buddy-style 9,000 BTU heater runs about 2.4 hours on high and closer to 5 hours on its low setting.
How long does a 20 lb propane tank last on a camp stove?
About 43 hours on a 10,000 BTU burner and about 19 to 20 hours on a 22,000 BTU two-burner stove run at full output. In real cooking terms that is a two-burner stove used for roughly three meals a day for a week, plus coffee. A 20 lb tank holds about 4.6 gallons, which is close to 19.5 lb of propane and roughly 430,000 BTU.
How much propane do I need for a 3-day camping trip?
For a family using a two-burner stove for two hot meals a day, plan on about 3 to 4 hours of burner time, which is well under one 20 lb tank and about 3 to 4 one-pound canisters. Boil water for coffee and washing up as well and you are closer to 5 cans. Carry one spare canister beyond your calculated number: running dry halfway through dinner is the one fuel problem you cannot fix at the campsite.
Is it cheaper to refill 1 lb propane cylinders?
Yes, by a wide margin. One-pound canisters bought in a 12-pack work out to about $5.42 each, which is roughly $25 per 100,000 BTU. A 20 lb refill at about $21 delivers the same 100,000 BTU for under $5, so bulk propane is about five times cheaper per unit of heat. A refill adapter plus a refillable 1 lb cylinder gets you the portability of a small canister at close to bulk prices.
How long will a 1 lb canister run a Buddy heater?
Roughly 2.4 hours on the 9,000 BTU high setting and about 5.4 hours on the 4,000 BTU low setting. Heaters are the fastest way to empty a one-pound can, so for a cold weekend most people bring a 20 lb tank and a hose assembly, or accept that a single canister is a one-evening supply. Never run a propane heater inside a tent.
Does cold weather change how long propane lasts?
It changes how well it flows, not how much energy is in the can. Propane boils at about minus 44 F, so straight propane cylinders keep working in hard cold, while isobutane canisters stop vaporising well below about 11 F and output drops off as the canister chills. Keep canisters above freezing in a sleeping bag or inside a jacket pocket, and expect noticeably longer boil times in wind because heat is lost around the pot.
Where to go next
- Camp stove fuel guide: propane vs butane vs isobutane — the full reference behind this calculator, with the fuel comparison tables.
- 1 lb vs 20 lb propane, cost per trip — the same cost maths run trip by trip for a family weekend.
- How much propane for camping — turning burn hours into a packing decision.
- How to refill 1 lb propane bottles safely — the refill workflow, done properly.
- Fuel canister safety and disposal — what to do with a spent canister, and what never to put in a fire.
Fuel prices vary by region and retailer, so the cost figures use typical street prices and state their assumption. TrailMapz earns a commission on qualifying Amazon purchases made through our links — it never changes what we recommend.