Work Out Your Tank Volume
Enter your tank's length, width and height and we'll work out how many litres it holds – plus a realistic water volume once substrate, rock and the waterline are accounted for.
Total volume is a straight L × W × H calculation. Water volume assumes substrate, rock and the waterline take up roughly 10% of that – your real number will vary with how much décor you run.
FAQ
Should I measure in cm or inches?
This calculator uses centimetres. If you've only got measurements in inches, multiply by 2.54 to convert to cm before entering them.
What's the difference between total volume and water volume?
Total volume is the raw internal capacity of the tank. Water volume is what's actually going to be full of water once substrate, rock, hardscape and the fact that you don't fill right to the rim are taken into account – it's the more realistic number for planning purposes.
Should I use inside or outside measurements?
Inside measurements are more accurate if you can get them. Outside measurements will slightly overestimate the true volume, since they include the glass thickness itself – the effect is small on nano tanks but can be a few litres on anything 120cm and up.
Why does this matter for dosing and stocking?
Our other calculators – like Alkalinity Dosing and the rest of the reef chemistry range – ask for your tank volume in litres. Use the water volume figure here, not the total volume, for the most accurate dosing results.