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Aquarium gallons to liters
Convert any common fish tank size between US gallons, UK gallons and liters at a glance. Every figure uses the exact conversion: 1 US gallon = 3.785411784 liters.
US gallons to liters
Nominal tank sizes as sold in the US. A 20-gallon tank holds about 75.7 liters and a 55-gallon about 208 liters. Real tanks often hold slightly more or less than their label, so check your exact size in the volume calculator.
| US gallons | Liters | UK gal |
|---|---|---|
| 5 US gal | 18.9 | 4.2 |
| 10 US gal | 37.9 | 8.3 |
| 15 US gal | 56.8 | 12.5 |
| 20 US gal | 75.7 | 16.7 |
| 29 US gal | 109.8 | 24.1 |
| 30 US gal | 113.6 | 25.0 |
| 40 US gal | 151.4 | 33.3 |
| 55 US gal | 208.2 | 45.8 |
| 65 US gal | 246.1 | 54.1 |
| 75 US gal | 283.9 | 62.5 |
| 90 US gal | 340.7 | 74.9 |
| 125 US gal | 473.2 | 104.1 |
| 150 US gal | 567.8 | 124.9 |
Liters to gallons
Common metric tank sizes sold in Europe, Latin America and Asia, in US and UK gallons. A 100-liter tank is about 26.4 US gallons or 22 UK gallons.
| Liters | US gal | UK gal |
|---|---|---|
| 20 L | 5.3 | 4.4 |
| 30 L | 7.9 | 6.6 |
| 40 L | 10.6 | 8.8 |
| 54 L | 14.3 | 11.9 |
| 60 L | 15.9 | 13.2 |
| 80 L | 21.1 | 17.6 |
| 100 L | 26.4 | 22.0 |
| 120 L | 31.7 | 26.4 |
| 150 L | 39.6 | 33.0 |
| 200 L | 52.8 | 44.0 |
| 240 L | 63.4 | 52.8 |
| 300 L | 79.3 | 66.0 |
| 400 L | 105.7 | 88.0 |
| 500 L | 132.1 | 110.0 |
US gallons vs UK gallons
They are different units. A US gallon is 3.785 liters, while a UK (imperial) gallon is 4.546 liters, about 20% larger. So a tank sold as 20 gallons in the US holds about 16.7 UK gallons. Tanks and products from the UK quote imperial gallons; most aquarium products sold worldwide use US gallons.
How to convert
Multiply US gallons by 3.785 to get liters, or divide liters by 3.785 to get US gallons. For UK gallons, use 4.546 instead. From tank dimensions, length × width × height in centimeters ÷ 1,000 gives liters, and in inches ÷ 231 gives US gallons.
Frequently asked questions
- How many liters is a 20 gallon fish tank?
- A 20 US gallon tank holds about 75.7 liters (20 × 3.785). A '20 long' (30 × 12 × 12 in) measures 70.8 liters from its outside dimensions, and a '20 high' (24 × 12 × 16 in) about 75.5 liters.
- How many liters is a 29 gallon tank?
- About 109.8 liters (29 × 3.785). The standard 29-gallon tank (30 × 12 × 18 in) measures 106.2 liters from its outside dimensions.
- How many liters is a 55 gallon tank?
- About 208 liters (55 × 3.785). The common 48 × 13 × 21 inch 55-gallon tank measures 214.7 liters from its outside dimensions and holds a little less water once you allow for the glass and substrate.
- How many gallons is a 100 liter aquarium?
- About 26.4 US gallons, or 22 UK gallons.
- How many gallons is a 200 liter tank?
- About 52.8 US gallons, or 44 UK gallons.