Tank Setup
Tank dimensions
Inches to centimeters, gallons to liters, and the nearest standard tank.
Footprint
Interior length × width × height. This is a rectangle only — bowfronts and cylinders belong on the volume calculator.
Also 76.2 × 30.5 × 30.5 cm.
Gallons ↔ liters
Converted tank
Rim-full
18.7 gal
Liters
71 L
Closest US nickname: 20 gallon long (30″ × 12″ × 12″). Best first community tank. Swim length beats a 20 high for tetras and corys.
Standard tanks
Click a row to load those inches. Nickname gallons are not water volume.
How to use this
- Enter interior length, width, and height in inches or centimeters.
- Read rim-full gallons and liters, plus the nearest US tank nickname.
- Use the gallons ↔ liters box for conditioner bottles and European listings.
- Click a standard tank to load its inches — then take those numbers to the volume calculator if the tank is not a rectangle.
Conversions
- 1 inch = 2.54 cm
- 1 US gallon = 3.785 L
- Rectangle gallons = L × W × H (inches) ÷ 231
US nicknames in inches and centimeters
A 20 high has the same gallons as a 20 long and a worse swim. European 60×30×30 cm is ~14 gallons, not a 20 long.
| Tank | Inches | Centimeters |
|---|---|---|
| 10 gallon | 20 × 10 × 12 | 51 × 25 × 30 |
| 20 long | 30 × 12 × 12 | 76 × 30 × 30 |
| 29 gallon | 30 × 12 × 18 | 76 × 30 × 46 |
| 40 breeder | 36 × 18 × 16 | 91 × 46 × 41 |
| 55 gallon | 48 × 13 × 21 | 122 × 33 × 53 |
| 75 gallon | 48 × 18 × 21 | 122 × 46 × 53 |
Worth knowing
- A 20 long is 30×12×12 inches. A 20 high is the same gallons and a worse swim.
- Rim-full is not water volume. Leave a gap at the top and subtract substrate.
- European 60×30×30 cm is roughly a 14-gallon, not a 20 long.
Usual mistakes
- Trusting the sticker gallons on a bowfront or 3D-printed rim.
- Buying a stand from centimeters and a tank from inches.
- Assuming two tanks with the same gallons have the same footprint.
See also: Tank volume · Substrate · Tank planner