Knowing your aquarium's exact volume is essential for proper fish keeping. This calculator helps you determine the water capacity of rectangular and cube-shaped aquariums.
Formula
The volume in gallons is calculated as:
[\text{Volume (gallons)} = \frac{\text{Length} \times \text{Width} \times \text{Depth}}{231}]
Where:
- All dimensions are in inches
- 231 is the number of cubic inches in a US gallon
Calculation Example
For an aquarium measuring 25" × 10" × 20":
[\text{Volume} = \frac{25 \times 10 \times 20}{231} = \frac{5000}{231} \approx 21.65 \text{ gallons}]
Metric Conversion
If measuring in centimeters, the calculator automatically converts to inches. Alternatively, for liters:
[\text{Volume (liters)} = \text{Length (cm)} \times \text{Width (cm)} \times \text{Depth (cm)} \times 0.001]
For example, 63.5 × 25.4 × 50.8 cm = 81.8 liters
Common Aquarium Sizes
| Dimensions (inches) | Approximate Volume |
|---|---|
| 20 × 10 × 12 | 10 gallons |
| 24 × 12 × 12 | 15 gallons |
| 24 × 12 × 16 | 20 gallons |
| 30 × 12 × 18 | 29 gallons |
| 36 × 18 × 16 | 45 gallons |
| 48 × 13 × 20 | 55 gallons |
Important Notes
- Actual water volume is typically 10-15% less than calculated due to substrate, decorations, and not filling to the brim
- For medications, use actual water volume to avoid overdosing
- Measure inside dimensions for accuracy, especially on thick glass tanks