Aquarium Volume Calculator
Calculate your aquarium’s water volume in litres and gallons, water weight, substrate needed, and get filter and heater recommendations based on tank shape and dimensions.
How the aquarium volume calculator works
This calculator estimates your tank’s water volume based on the shape and dimensions you enter. It supports rectangular, cylindrical, hexagonal, and bow-front tanks. Simply select your tank shape, enter the dimensions in cm, inches or feet, and choose your substrate depth to get:
— Total water volume in litres and US/UK gallons
— Water weight in kilograms and pounds
— Substrate amount needed in kg
— Filter flow rate recommendation (L/h)
— Heater wattage recommendation (W)
Step 1: Tank Information
Understanding Aquarium Volume
Knowing your tank’s exact water volume is essential for correct dosing of water conditioners, medications, choosing the right filter, heater, and stocking fish safely.
Step 2: Setup Details
Aquarium Setup Tips
For a healthy aquarium, choose a filter that cycles 4–6× your tank volume per hour. For heating, use 1 W per litre as a baseline, adjusting for room temperature.
Aquarium Volume Results
Total Water Volume
Shape Volume Comparison
| Tank Shape | Volume (Litres) | Volume (US Gal) | Volume (UK Gal) |
|---|
Volume Breakdown by Shape
Volume Calculation Formulas
Shape-specific formulas
Rectangular: L × W × H
Cylindrical: π × (D/2)² × H
Hexagonal: (3√3/2) × side² × H
Bow Front: (L × W × H) + (π × (bow/2)² × H / 2)
All dimensions converted to centimetres for calculation. Results shown in litres (÷1,000) and gallons (×0.264172 US, ×0.219969 UK).
Frequently Asked Questions
How do you calculate aquarium volume?
Aquarium volume is calculated by multiplying the length, width, and height of the tank (for rectangular tanks). For cylindrical tanks, use π × radius² × height. The result is then converted from cubic centimetres to litres (÷1,000) and to gallons (×0.264172 for US gallons).
How many litres is my fish tank?
Measure your tank’s length, width and height in centimetres, multiply them together (L × W × H), then divide by 1,000. That gives you the volume in litres. For example, a 60cm × 30cm × 40cm tank = 72 litres.
What is the best filter for my aquarium size?
A good rule of thumb is that your filter should process 4–6 times your tank’s total water volume per hour. For a 100-litre tank, look for a filter with a flow rate of 400–600 litres per hour.
How much substrate do I need for my aquarium?
To calculate substrate needed, multiply the tank’s length × width × desired substrate depth (in cm), then divide by 1,000 to get litres. For gravel, use about 1.5 kg per litre of substrate volume. For sand, use about 1.3 kg per litre.
What size heater do I need for my aquarium?
A general guideline is 1 watt per litre of water. So a 100-litre tank needs a 100-watt heater. For rooms that are very cold, you may need 1.5–2 watts per litre.
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