55 Gallon Drum dimensions

Nominal rating versus real geometry

A tank's name is a trade label. Its geometry is a measurement. On a steel drum these two numbers are related but not equal, and knowing which one you are quoting matters whenever the figure ends up on an invoice, a permit or a purchase order.

Rated 55 gal. Computed from the dimensions in the table above: 57.7 gal. The shell is built oversize by 2.7 gallons — 4.9 % — against its label. That headroom is deliberate: it is ullage for thermal expansion and outage, not capacity you are meant to use.

Densities are the reference values tabulated on our methodology page, near 60–70 °F. Real fluids vary with temperature, grade and composition — a 10 °F swing moves a hydrocarbon density by roughly 0.4 %. Add the empty vessel weight to get a gross figure.

Handling and storage

A full drum of anything water-like is well over 400 pounds, which is past what one person should be moving by hand. Use a drum dolly or a forklift drum attachment; 'walking' a drum on its chime is how backs and toes get hurt, and a drum that tips is not catchable.

Store upright with the bungs at roughly the 12 and 6 o'clock positions if the drum must lie horizontal, so that both closures stay below the liquid line and the gaskets stay wet. Drums stored outdoors on their sides with a bung at 3 o'clock will breathe water in as they cool.

For secondary containment, size to the drum, not to the pallet: the SPCC rule asks for the capacity of the largest single container plus freeboard, which for a 55-gallon drum means at least 55 gallons of sump.

The standards behind this container

Steel drums for regulated materials are built to 49 CFR § 178.504 and coded under § 178.502: 1A1 for a non-removable (tight) head and 1A2 for a removable (open) head. Openings larger than 3 inches make a drum removable-head by definition. The older DOT-17E designation you still see quoted in trade literature was superseded by these UN performance-oriented standards, and a modern drum carries a UN mark rather than a 17E stamp.

The nominal 55 gallons is a rated fill capacity, not a brim capacity — a standard tight-head drum holds several gallons more before it overflows, and the difference is deliberate outage for thermal expansion.

For storage, the SPCC rule treats drums as portable containers under 40 CFR § 112.8(c)(11): secondary containment must hold the largest single container plus freeboard, which for a single 55-gallon drum means a sump of at least 55 gallons, not the 30-gallon two-drum platforms often sold for the purpose.

For depth-by-depth volumes on this tank, use the inch-by-inch chart; for a different set of dimensions, the dip chart generator will build one.

Sources and standards

The geometry on this page is computed, not copied. These are the documents that define the units it is expressed in and the codes that govern a steel drum in service.

1. 49 CFR § 178.504 — Standards for steel drums (and § 178.502, identification codes)U.S. Pipeline and Hazardous Materials Safety Administration, via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-178/subpart-L/section-178.504The current federal standard for steel drums. Codes are 1A1 (non-removable head) and 1A2 (removable head); openings over 3 inches make a drum removable-head by definition. The legacy DOT-17E designation was superseded by these UN performance-oriented standards.
2. 49 CFR Part 178 — Specifications for Packagings (Subpart N: Intermediate Bulk Containers)U.S. Pipeline and Hazardous Materials Safety Administration, via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-178Design, construction, marking and periodic retest requirements for IBCs. The UN marking moulded into a tote's bottle records its design type, packing group, test date and rated capacity — read it before trusting a nominal gallon figure.
3. 40 CFR § 112.8(c)(2) — Spill Prevention, Control, and Countermeasure Plan requirements for onshore facilitiesU.S. Environmental Protection Agency, via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-40/chapter-I/subchapter-D/part-112/subpart-B/section-112.8Requires secondary containment sized for the entire capacity of the largest single container, plus sufficient freeboard to contain precipitation. Note that the rule itself does not state “110 %” — that is a common design convention layered on top of the regulatory floor.
4. Handbook 44, Appendix C — General Tables of Units of MeasurementNational Institute of Standards and Technology, U.S. Department of Commercehttps://www.nist.gov/document/2026-nist-handbook-44-appendix-cThe legal-metrology reference for U.S. customary units. Fixes the U.S. liquid gallon at exactly 231 cubic inches and tabulates the full liquid-volume chain (minim → fluid dram → fluid ounce → gill → pint → quart → gallon).
5. Methodology — the partial-fill formulas and liquid densities used on this sitetankvolumecalc.comhttps://tankvolumecalc.com/methodology/Every chart value here comes from a closed-form partial-fill formula, not interpolation: circular segments for cylinders, a piecewise obround model for 275/330 heating-oil tanks, and scaled spherical caps for dished heads. Densities and their bases are tabulated there.

Every linked source above was retrieved and checked on 2026-09-02. Factors quoted as exact are exact by definition in the cited document, not rounded by us.