120 gallon tank: dimensions & setup math
48 × 24 × 24 inches (L × W × H). Rounded planning dimensions; measure your tank.
120 nominal gal · about 1,297.08 lb with water, estimated glass and 2-inch gravel.
Estimated working water uses 85% of nominal: 102 US gal. The volume tool instead applies 85% to geometric volume. Neither is a measured fill.
Eight answers for this tank
- Tank volume
119.69 US gallons · 453.07 litres
- Gravel & substrate
133.33 lb gravel for a 2-inch bed
- Heater wattage
360–600 W planning range
- Filter flow
480–720 GPH for a community
- Stocking guide
1,152 in² surface · 48-inch swimming length
- Water changes
25.5 US gal for a 25% water change
- Dechlorinator dose
12 mL Prime for 120 US gal of new water
- Filled weight
About 1,297.08 lb filled (without stand)
Plan around this footprint
This 120 gallon plan uses 48 × 24 × 24 inches and 1,152 in² of floor. Compared with the 110 gallon (864 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.