Propane Tank Sizes
Propane tank sizes run from 20 lb grill tanks to 1,000-gallon home tanks, and the labels can be confusing: grill tanks are sold by weight, home tanks by gallons, and neither is ever filled to the number on the side. Below I explain what each size actually holds, which one fits your home and, most usefully, how long a full tank will last.
By Nathan Brooks · Reviewed Oct. 15, 2026 · Capacities and dimensions from major U.S. propane suppliers
Home propane tank sizes
| Tank | Holds when full | Typical size | Best for |
|---|---|---|---|
| 120 gal (420 lb) | about 96 gal | 4′6″ tall, 30″ wide (upright) | 1–2 appliances: water heater, range, dryer or fireplace |
| 250 gal | about 200 gal | 7′10″ long, 30″ wide | Small homes, or 2–3 appliances without whole-home heat |
| 500 gal | about 400 gal | 9′11″ long, 37.5″ wide | Whole-home heating for most houses |
| 1,000 gal | about 800 gal | 16′2″ long, 41″ wide | Large homes, cold climates, all-propane homes |
Dimensions vary slightly by manufacturer. Tanks can be above ground or buried (buried tanks usually start at 250 gallons).
Which size do you need?
| Your home | Usual tank |
|---|---|
| Propane only for a range, dryer or fireplace | 100 lb cylinders or 120 gal |
| Water heater + 1–2 small appliances | 120–250 gal |
| Propane heat, up to about 2,500 sq ft | 500 gal |
| Propane heat, over 2,500 sq ft or a very cold area | 500–1,000 gal |
| Heat + generator + pool heater | 1,000 gal |
A bigger tank costs more to install but means fewer deliveries and lets you buy more propane when prices are low, usually in late summer. If you heat with propane, most suppliers recommend a tank large enough that you need no more than a few deliveries each winter. That’s the right goal: every delivery in the middle of a cold snap is one you might pay more for, or wait longer for.
Portable cylinder sizes
| Cylinder | Propane | Energy | Common use |
|---|---|---|---|
| 1 lb (disposable) | about 0.24 gal | about 21,600 BTU | Camping stoves, lanterns |
| 20 lb | about 4.7 gal | about 430,000 BTU | Grills, patio heaters |
| 30 lb | about 7.1 gal | about 650,000 BTU | RVs, campers |
| 33 lb | about 7.8 gal | about 710,000 BTU | Forklifts |
| 40 lb | about 9.4 gal | about 860,000 BTU | RVs, food trucks |
| 100 lb | about 23.6 gal | about 2.16 million BTU | Water heaters, generators, cabins |
Propane weighs about 4.24 lb per gallon and contains about 91,500 BTU per gallon (U.S. EIA). Figures are rounded.
How long will my propane tank last?
Home tanks: 80% on the gauge = full.
Find it on the appliance label or manual.
A furnace in cold weather often runs 6–12 hours a day in total.
Estimate based on 91,500 BTU per gallon and the appliance running at its full rating. Real use is usually lower because burners cycle on and off.
A real-world example: one tank, one winter
Numbers on a spec sheet don’t mean much until you see them in a winter. Take a 500-gallon tank, filled to 80%, so about 400 gallons. A 100,000 BTU furnace running 8 hours a day uses about 800,000 BTU, or close to 9 gallons a day. At that pace, a full tank lasts roughly 46 days. Over a long, cold winter, that adds up to several fills.
That’s why it pays to check your gauge before the first cold week and order at about 30%, not 10%. Running low in January is how people end up paying for emergency deliveries. — Nathan Brooks
Buy or lease a home tank?
- Leasing is common: the supplier owns the tank, installs and maintains it, and you usually must buy propane only from them. It’s easy, but you lose the ability to shop around.
- Owning costs more up front, but you can shop around for the best price per gallon every time you fill. Over many years that can add up to real savings. I go through the math in leased vs. owned propane tanks.
- Before you sign, ask about yearly tank rental fees, minimum-use fees and what it costs to remove the tank if you switch suppliers. Get the answers in writing.
Why tanks are filled to 80%
Propane expands as it warms, so home tanks are filled to about 80% to leave room for that expansion. That’s normal, not a short fill. Portable cylinders from 4 to 40 lb need an overfill prevention device (OPD, the triangle-shaped valve handle) to be refilled; it stops filling at a safe level. Older cylinders without an OPD can’t be refilled. Where to refill propane.
Quick answers
What size propane tank do I need for my house?
If propane heats your home, most houses use a 500-gallon tank, which holds about 400 gallons. Larger homes, very cold areas or homes that also run a generator or pool heater often use a 1,000-gallon tank.
How many gallons are in a 100 lb propane tank?
About 23.6 gallons when full, since propane weighs about 4.24 lb per gallon.
How long does a 20 lb propane tank last on a grill?
About 10 to 20 hours of grilling. A 20 lb tank holds roughly 430,000 BTU, and a typical grill uses 20,000 to 40,000 BTU an hour depending on the burners and heat level.
How long does a 500-gallon propane tank last?
It depends on your home and climate. A full tank holds about 400 gallons. A home using 700 to 1,000 gallons a year for heat might need two or three fills per year.
Can a propane tank be buried?
Yes. Underground tanks usually start at 250 gallons. They cost more to install but are hidden from view and handle extreme temperatures better.
Keep saving
Sources
AmeriGas: propane tank sizes · Ferrellgas: propane tank sizes · Suburban Propane: tank sizes · EIA: energy content of fuels
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