TankMathLess guesswork. Better tank plans.

75 gallon tank: dimensions & setup math

48 × 18 × 21 inches (L × W × H). Rounded planning dimensions; measure your tank.

78.55 geometric US gal · 297.33 L

75 nominal gal · about 854.08 lb with water, estimated glass and 2-inch gravel.

Estimated working water uses 85% of nominal: 63.75 US gal. The volume tool instead applies 85% to geometric volume. Neither is a measured fill.

Eight answers for this tank

Plan around this footprint

This 75 gallon plan uses 48 × 18 × 21 inches and 864 in² of floor. Compared with the 65 gallon (648 in²), its footprint is 33.33% larger. Large setup: plan hose access, independent temperature checks and a purpose-built stand before filling.

Dimensions and limits

Aqueon size chart. Listed dimensions are representative, not exact catalog measurements. Names identify marketed sizes; geometry explains why the calculated gallons can differ. Weight excludes the stand, rocks and equipment.