Volume Fish Tank Calculator
Volume of fish tank calculator works out Total capacity and Volume at the measured depth from Tank shape, Length and Width. The default figures on this page give total capacity of 44.88 US gal; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
4 steps
- Shape: 0.9144 x 0.4572 x 0.4064 m.
- Capacity = 0.169901 m3 = 169.9 L = 44.88 US gal = 6 cu ft.
- No fill depth was given, so only the full capacity is reported.
- Full, the contents weigh 0.169901 m3 x 1000 kg/m3 = 169.9 kg (374.6 lb), before the weight of the tank, substrate or rock.
Its 4 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
3 sources
Keep this result
Save it, change one figure, then compare the two
The calculation stays free. Save this scenario, adjust one assumption, save that too, and put them side by side to see exactly what the change costs you. A free account keeps 5 scenarios and 2 comparisons; Personal makes both unlimited and adds exports and private links. Nothing is saved unless you press Save.
What the volume of fish tank calculator calculates
Computes the capacity of a tank, cistern or aquarium in litres, US and imperial gallons, cubic feet and cubic metres for eight shapes, and the volume actually held at a measured fill depth.
How to use this volume of fish tank calculator
Enter Tank shape, Length, Width and Height (straight side). Total capacity updates as you type. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Total capacity, Volume at the measured depth and Space still free.
The method follows Closed-form solid geometry: prism, cylinder, sphere, spherical cap and circular segment, NIST Special Publication 811, Guide for the Use of the International System of Units and Researched engineering contract R1767 (aquarium volume, V = L x W x H).
What you can compare
Change one input at a time to see how it affects Total capacity, Volume at the measured depth and Space still free. The inputs you can vary are Tank shape, Length, Width, Height (straight side), Diameter and Measured fill depth.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
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Frequently asked questions
How many gallons does a 24x16x12 fish tank hold?
On the figures this page opens with — length 36, width 18 and height (straight side) 16 — the total capacity is 44.88 US gal. No single number fits everyone: change any figure above and the answer updates as you type, with each step of the arithmetic beside it.
How many gallons is a 24x12x12 fish tank?
It needs Tank shape, Length, Width, Height (straight side), Diameter and Measured fill depth. Nothing else is required, and the figures stay in your browser.
How many gallons is a 36x17x18 tank?
The result gives Total capacity, Volume at the measured depth, Space still free, Fill level and Weight of the contents when full, each labelled with its unit so the figure can be read on its own.
How many gallons is a 20x10x12 tank?
The page opens with worked default figures: total capacity of 44.88 US gal. Replace them with your own and every figure updates as you type.
What information do I need for the volume of fish tank calculator?
You need Tank shape, Length, Width, Height (straight side), Diameter, Measured fill depth, Unit for the dimensions and Liquid density. The page opens with default figures that give total capacity of 44.88 US gal, so you can see the scale before entering your own.
What does this volume of fish tank calculator show?
It shows Total capacity, Volume at the measured depth, Space still free, Fill level and Weight of the contents when full, with the working and any warnings for your entries.