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Aquarium Volume Calculator

Enter your tank's inside measurements — the volume in litres and gallons updates as you type.

Aquarium volume calculator

Tank shape
Tank dimensions
bare tankheavily decorated

Rock, wood and sand take up space. 5–15% is typical for a planted tank.

Common sizes

US / imperial sizes

Metric sizes

60 cm30 cm30 cm
Water fills 100% of the volume · substrate and hardscape take 0%

Results

Actual water volume

54L

≈ 14.27 US gal · 11.88 UK gal

Gross volume
54 L

empty tank, to the brim

Gross volume
14.27 US gal
Imperial gallons
11.88 UK gal

actual water

Water mass
54 kg

≈ 1 kg per litre

Based on 60 × 30 × 30 cm filled to the brim, with nothing inside.

How this aquarium calculator works

Type the inside dimensions of your tank in centimetres, inches or feet and the volume updates as you type — no “calculate” button needed. The formula is simple: length × width × height gives the gross volume, which is then converted to litres, US gallons and UK gallons. Add a displacement percentage to estimate the actual water volume once substrate, rocks and wood are in.

Want the full walkthrough, the formulas, a common tank sizes table and an FAQ? Read the complete aquarium volume guide — it covers gross vs actual volume, litres ↔ gallons conversions and how much water mass to expect for floor and stand planning.

Planning equipment next? Our guides section explains how volume feeds into heater sizing, filter flow and stocking decisions.