Propane Tank Sizes
Every common propane tank size, from the 20 lb grill cylinder to the 1,000 gallon home tank, with typical dimensions and how much propane each one actually holds in gallons and pounds.
How much propane is in my tank?
The float gauge on a bulk tank shows the percent of the whole tank, so a full tank reads about 80%.
Propane in tank
200 gal
Weight of propane
840 lb
Room to fill (to 80%)
200 gal
Propane cylinder sizes (portable tanks)
| Cylinder | Propane (lb) | Propane (gal) | Typical size | Common use |
|---|---|---|---|---|
| 20 lb | 20 | 4.8 | 18" tall × 12–12.5" dia. | Gas grills, RVs |
| 30 lb | 30 | 7.1 | 24" tall × 12.5" dia. | RVs and campers |
| 33 lb | 33 | 7.9 | 26.75–29" tall × 12.5–13" dia. | Forklifts, RVs |
| 40 lb | 40 | 9.5 | Varies by maker | Larger portable supply |
| 100 lb | 100 | 23.8 | about 48" tall × 14.7–15" dia. | RVs (largest common cylinder) |
Gallons are calculated at 4.2 lb per gallon. Suppliers often quote slightly less, for example 4.7 gal for a 20 lb cylinder and 23 gal for a 100 lb cylinder.
Residential propane tank sizes (bulk tanks)
| Tank | Propane at 80% | Propane weight | Typical size | Common use |
|---|---|---|---|---|
| 120 gal | 96 gal | 403 lb | 54.5" tall × 30" dia. (vertical) | One or two appliances: water heater, fireplace, space heater |
| 250 gal | 200 gal | 840 lb | 7'10" long × 30" dia. | Dryer, fireplace, range, or heating a modest home |
| 325 gal | 260 gal | 1,092 lb | 10' long × 30" dia. | Backup generators, smaller homes |
| 500 gal | 400 gal | 1,680 lb | 9'11" long × 37.5" dia. | Whole-house heating for most homes |
| 1,000 gal | 800 gal | 3,360 lb | 16'1.5" long × 41" dia. | Large homes and commercial use |
Safety notes
- Keep portable cylinders upright and outdoors; never store them indoors or in a garage.
- Only a trained supplier should fill or move bulk tanks.
- If you smell gas, leave the area and call your propane supplier or 911 from outside.
Propane Tank Sizes FAQ
How many gallons are in a 20 lb propane tank?
About 4.7 gallons. Propane weighs roughly 4.2 lb per gallon at 60 °F, so 20 lb ÷ 4.2 ≈ 4.8 gallons, and suppliers usually quote 4.7. The empty steel cylinder adds roughly 17–19 lb (its tare weight is stamped on the collar).
Why does a 500 gallon tank only hold 400 gallons?
Bulk tanks are named by their water capacity and filled to about 80% so the liquid has room to expand as it warms. A 500 gallon tank therefore holds about 400 gallons of propane, and a 1,000 gallon tank about 800.
What size propane tank do I need for my house?
A 500 gallon tank is the usual choice for whole-house heating. A 120 to 250 gallon tank suits one or two appliances such as a water heater, range, or fireplace, while 1,000 gallons is for large homes and commercial use. Your propane supplier will size it from your appliances and climate.
Are propane tank dimensions the same for every brand?
No. Dimensions vary a few inches between manufacturers, and some sizes come in vertical and horizontal styles. Use these as typical sizes for planning, and confirm with the supplier before preparing a pad or enclosure.
Sources
Propane density of about 4.2 lb per gallon at 60 °F (Wikipedia, “Propane”). Typical dimensions, 80% fill practice, and uses from the Ferrellgas propane tank size guide; the 100 lb cylinder dimensions match Manchester Tank retail listings. Dimensions vary by manufacturer.