TankMathLess guesswork. Better tank plans.

90 gallon tank: dimensions & setup math

48 × 18 × 24 inches (L × W × H). Rounded planning dimensions; measure your tank.

89.77 geometric US gal · 339.8 L

90 nominal gal · about 993.18 lb with water, estimated glass and 2-inch gravel.

Estimated working water uses 85% of nominal: 76.5 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 90 gallon plan uses 48 × 18 × 24 inches and 864 in² of floor. Compared with the 75 gallon (864 in²), its footprint is 0% 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.