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100 gallon tank: dimensions that work

100 gal = 379 L = 13.4 ft³. Full weight ≈ 835 lb of water. Below: every diameter/length pair that holds exactly this — geometry, not brand specs, so you can sanity-check any manufacturer sheet.

Horizontal cylinder: length required for 100 gal
DiameterLength
24 in dia51 in (4.3 ft)
30 in dia33 in (2.7 ft)
Vertical cylinder: height required for 100 gal
DiameterHeight
24 in dia51 in tall
30 in dia33 in tall

Have a real tank with these dimensions? Generate its inch-by-inch dip chart, or run partial fills on the universal calculator. Manufactured tanks add heads, legs and fittings — treat these tables as the geometric core and trust the nameplate where one exists.

FAQ

How big is a 100 gallon tank?

It depends on the proportions — the tables above show every horizontal length and vertical height that holds exactly 100 gallons at common diameters. Pure geometry: πr²L = 100 × 231 in³.

How much does 100 gallons weigh?

About 835 lb as water or 705 lb as diesel — grade ranges and more liquids on the weight library.

How many litres is 100 gallons?

379 litres (0.4 m³). Exact: 1 US gal = 3.785411784 L.