CALCULATOR

Aquarium Volume

Gallons and liters from your tank dimensions — results update as you type.

Length (inches)

Width (inches)

Height (inches)

14.9

gallons

≈ 56.5 liters · 12.7 gal usable

How volume works

Volume = Length × Width × Height ÷ 231 (gallons). A 24×12×12 tank is 15 gallons. Fish need usable water — subtract 10-15% for substrate, decor, and water level below the rim.

Common tank	Gallons	Liters
20" × 10" × 12"	10	38
24" × 12" × 16"	20	76
30" × 12" × 18"	29	110
48" × 13" × 21"	55	208

Then use the stocking calculator to see how many fish fit.