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