Aquarium Gallons to Liters Conversion Table
1 US gallon equals exactly 3.785411784 liters (SI-defined). The table below converts common US-gallon aquarium sizes to liters, and common metric sizes back to US gallons, so you can compare a tank listed in either unit without rounding it yourself. Compiled 2026-09-25.
| US gallons | Liters |
|---|---|
| 1 | 3.8 |
| 2 | 7.6 |
| 5 | 18.9 |
| 10 | 37.9 |
| 15 | 56.8 |
| 20 | 75.7 |
| 25 | 94.6 |
| 29 | 109.8 |
| 30 | 113.6 |
| 40 | 151.4 |
| 50 | 189.3 |
| 55 | 208.2 |
| 65 | 246.1 |
| 75 | 283.9 |
| 90 | 340.7 |
| 100 | 378.5 |
| 110 | 416.4 |
| 120 | 454.2 |
| 125 | 473.2 |
| 150 | 567.8 |
| 180 | 681.4 |
| 200 | 757.1 |
| 250 | 946.4 |
| 300 | 1135.6 |
| Liters | US gallons |
|---|---|
| 50 | 13.2 |
| 75 | 19.8 |
| 100 | 26.4 |
| 150 | 39.6 |
| 200 | 52.8 |
| 250 | 66 |
| 300 | 79.3 |
| 400 | 105.7 |
| 500 | 132.1 |
| 600 | 158.5 |
Why the exact constant matters
Rounding the gallon-to-liter constant (using 3.8 or 3.79 instead of 3.785411784) compounds on large tanks: a 180 gallon tank differs by more than a liter between a rounded and an exact conversion. TankStockPlan's own calculator works entirely in metric internally (centimeters and liters), so any gallon figure you see on a size chart or tank label is converted using this exact constant before the usable-volume math runs.