Propane tank sizes & dimensions
Every common propane tank, from the 5 lb camping cylinder to the 1,000 gallon home-heating tank, with height or length, diameter, empty weight and how much propane each actually holds — all from Manchester Tank's own published sheets.
Reading a gauge or a stick? The propane tank calculator gives gallons at any level, and the tank charts cover 120 to 1,000 gallons.
Portable cylinders — sized in pounds
Grill, RV, forklift and patio-heater cylinders are DOT cylinders. They are filled by weight to 42 % of their water capacity, so the size is the pounds of propane inside.
| Size | Height | Diameter | Empty | Full | Propane |
|---|---|---|---|---|---|
| 5 lb | 12.5 in | 8.06 in | 10 lb | 15 lb | 1.3 gal |
| 10 lb | 17.3 in | 9 in | 15 lb | 25 lb | 2.6 gal |
| 11 lb | 12.4 in | 12.2 in | 14 lb | 25 lb | 2.6 gal |
| 20 lb | 18 in | 12.2 in | 18 lb | 38 lb | 4.7 gal |
| 30 lb | 23.4 in | 12.2 in | 25 lb | 55 lb | 7.1 gal |
| 40 lb | 29.4 in | 12.2 in | 32 lb | 72 lb | 9.5 gal |
| 50 lb | 28.3 in | 14.9 in | 42 lb | 92 lb | 11.9 gal |
| 60 lb | 43.1 in | 12.5 in | 46 lb | 106 lb | 14.3 gal |
| 100 lb | 47.5 in | 14.9 in | 70 lb | 170 lb | 23.8 gal |
| 200 lb | 41.9 in | 24 in | 152 lb | 352 lb | 45.6 gal |
| 420 lb (sold as “100 gallon”) | 53.8 in | 30 in | 278 lb | 698 lb | 95.9 gal |
Full weights are the empty weight plus the rated propane. For water capacity and DOT specification of each size see propane cylinder sizes.
Home and farm tanks — sized in gallons
Stationary ASME tanks are named by water capacity. They are filled to about 80 % of it, so the propane they hold is four-fifths of the name.
| Size | Diameter | Overall length | Overall height | Heads | Empty | Propane at 80 % | Part |
|---|---|---|---|---|---|---|---|
| 120 gal | 24 in | 5′ 8″ | 2′ 10¼″ | Elliptical | 302 lb | 96 gal | 68268 |
| 250 gal | 30 in | 7′ 10″ | 3′ 4 3⁄16″ | Hemispherical | 457 lb | 200 gal | 68270 |
| 320 gal | 30 in | 9′ 7″ | 3′ 4 3⁄16″ | Hemispherical | 563 lb | 256 gal | 68272 |
| 500 gal | 41 in | 8′ 8½″ | 3′ 6 15⁄16″ | Hemispherical | 972 lb | 400 gal | 68303.20 |
| 1000 gal | 41 in | 15′ 8½″ | 3′ 6 15⁄16″ | Hemispherical | 1,759 lb | 800 gal | 68304.20 |
Dimensions are outside measurements and, in Manchester's words, approximate; the height includes the legs. Other manufacturers build the same capacities to different proportions, so measure yours before planning a pad or a clearance. The manufacturer tank registry has the full Manchester specification for each part number.
Underground tanks, and the vertical 120 gal ASME tank sold for exchange service, are not in this table. Where a tank may go relative to buildings and property lines is set out in the propane tank reference.
FAQ
How do I tell what size my propane tank is?
A portable cylinder is stamped on its collar with WC (water capacity, in pounds) and TW (tare weight, empty, in pounds); its size in pounds of propane is about 42 % of the WC. A larger stationary tank has a data plate giving its water capacity in gallons — that number is its size.
What is the 80/20 rule for propane tanks?
Stationary tanks are filled to no more than about 80 % of their water capacity, leaving roughly 20 % as vapour space for the liquid to expand into as it warms. That is why a 500 gallon tank holds about 400 gallons of propane and its gauge stops near 80 %.
Why are small tanks sized in pounds and big ones in gallons?
Portable DOT cylinders are filled by weight, so they are named by the pounds of propane they hold — a 20 lb cylinder holds 20 lb. Stationary ASME tanks are filled by volume and named by water capacity in gallons.
How big is a 500 gallon propane tank?
Manchester Tank's 500 gallon tank is 41 in in diameter and 8′ 8½″ long overall; other makers build the same capacity to different proportions. It holds about 400 gallons of propane at the 80 % fill.
How many gallons are in a 20 lb propane tank?
About 4.7 gallons of propane when full, by Manchester Tank's catalog — 20 lb divided by propane's 4.24 lb per gallon.
Sources and standards
- DOT 5 lb. – 100 lb. Catalog 49500 (09/2022)Manchester Tank & Equipment Co. — manufacturerhttps://www.mantank.com/upl/downloads/content-blocks/portable-dot-lpg-cylinders-5lb-to-100lb.pdf
- Steel Tanks & Cylinders for LP Gas Systems, Portable Steel Tanks Catalog 49501 (2020)Manchester Tank & Equipment Co. — manufacturerhttps://www.mantank.com/upl/downloads/content-blocks/tanks-cylinders-for-lpg-systems-100lb-to-420lb.pdf200 lb and 420 lb cylinders.
- Aboveground Propane Tanks, 120–1000 gallons (Rev. 4/11/2025)Manchester Tank & Equipment Co. — manufacturerhttps://www.mantank.com/upl/downloads/content-blocks/aboveground-horizontal-domestic-propane-tanks.pdfPart number, water capacity, outside diameter, head type, overall length and height, leg spacing and weight for each ASME tank. “All Vessel Dimensions are Approximate.”
- 49 CFR § 173.304a — filling densities for liquefied compressed gasesU.S. Department of Transportation (PHMSA), via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-173/subpart-G/section-173.304aPropane in DOT cylinders: filled by weight to 42 % of water capacity.
- NFPA 58 — Liquefied Petroleum Gas Code (filling limits, Ch. 7)National Fire Protection AssociationPaid standard — cited by designation; obtain from the publisher.
Every linked source above was retrieved and checked on 2026-11-01.