Fish Tank Calculator

Calculate the volume, capacity, and maintenance requirements for your aquarium.

Using same unit as length
Using same unit as length
Recommended: 90%

When setting up a fish tank, it's recommended to leave some space at the top for:
- Water movement and oxygenation
- Fish jumping
- Maintenance access
The standard recommendation is to fill to about 90% capacity.

Fish Tank Volume and Capacity Calculator

Calculate the volume and water capacity of your aquarium with our easy-to-use calculator. Learn about fish tank measurements, stocking guidelines, and maintenance requirements.

An aquarium's volume is crucial for maintaining a healthy environment for aquatic life. This calculator helps you determine your tank's capacity in both gallons and liters, essential for proper fish stocking, filtration, and water treatment calculations.

Formula

Volume (cm³) = L × W × H
Gallons = Volume (cm³) ÷ 3785.41
Liters = Volume (cm³) ÷ 1000

Where:

  • L:length of the aquarium
  • W:width of the aquarium
  • H:height of the aquarium

How to Calculate Tank Volume

Measure your tank's length, width, and height in consistent units. Multiply these dimensions to get the volume. For irregular shapes or bow-front tanks, use the average width. Remember to account for substrate and decorations.

Understanding Fish Capacity

The general rule is one inch of fish per gallon of water for small fish. Larger fish need more space. Consider fish species, adult size, swimming habits, and territorial behavior when stocking.

Maintenance Requirements

Tank volume determines filter capacity needs, water change volumes, and chemical dosing. Larger tanks are more stable but require more maintenance. Regular water changes of 10-25% weekly are recommended.

Frequently Asked Questions

How much substrate should I add?

For most setups, add 1-2 inches of substrate. This reduces your tank's water volume by about 10%. For planted tanks, use 2-3 inches. Calculate substrate volume as Length × Width × Substrate Depth.

How do I calculate water for partial changes?

Multiply your tank's volume by the percentage you want to change. For example, for a 20% water change in a 50-gallon tank, you'd need to replace 10 gallons (50 × 0.20 = 10).

What affects my tank's true capacity?

Decorations, equipment, substrate, and plants reduce the actual water volume. A general rule is to subtract 10-15% from the calculated volume to account for these items.

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