About AquariumVolume.com

AquariumVolume.com was created by Daniel Hartley, a freshwater and marine aquarium hobbyist with over four years of hands-on experience keeping and maintaining tanks ranging from 10-gallon nano setups to 125-gallon display systems. The frustration of finding inaccurate volume calculators online — particularly for non-rectangular shapes like bow fronts, hexagons, and corner cylinders — led to building a dedicated resource covering all 20 common tank shapes with verified geometric formulas.

Daniel built this site in 2026 with one goal: a calculator resource accurate enough to use for medication dosing, not just for curiosity. Every formula has been verified against known tank volumes and cross-checked against manufacturer-published specifications.

Knowing your tank’s precise water volume matters more than many fishkeepers realise. Medication and water treatment dosing is calculated per gallon or litre — an error of even 20% can mean underdosing a parasite treatment or dangerously overdosing a supplement. Stocking density recommendations depend entirely on accurate volume. Equipment sizing — heater wattage, filter flow rate, protein skimmer capacity for reef tanks — is also specified by volume. A calculator that returns the wrong figure sets off a chain of incorrect decisions throughout the life of your aquarium.

Every calculator on this site applies the correct geometric formula for that specific tank shape. A rectangular tank uses length × width × height divided by 231 to convert cubic inches to US gallons. A bow front tank requires an additional half-ellipse calculation for the curved section. A hexagonal tank uses the regular hexagon area formula. A corner cylinder is exactly one quarter of a full cylinder’s volume. The formula is displayed on every calculator page so you can verify the math yourself. Results are shown in both US gallons and litres simultaneously.

All calculators ask for inside dimensions, not outside measurements. The glass or acrylic walls of an aquarium have meaningful thickness — typically ¼ inch on small tanks and up to ¾ inch on large display setups. Measuring the exterior and treating it as the interior will overstate your volume by 5–8% on large tanks. Our measurement guide on each calculator page explains exactly where to place your tape measure to get the correct inside dimension.

All formulas are derived from standard geometric volume equations and have been independently verified against known tank volumes. The rectangular formula has been cross-checked against manufacturer-published specifications for Aqueon, Marineland, and Fluval tanks. Where nominal label volumes differ from calculated volumes, we explain why on the dedicated aquarium volume by brand reference page.

AquariumVolume.com launched in 2026 and currently covers 53 pages across 20 individual tank shape calculators, 5 calculator category hubs, 5 side-by-side shape comparison guides, 9 reference pages and measurement guides, 3 specialist tools, and supporting pages. All content is focused exclusively on aquarium volume — we do not cover fish care, species guides, product reviews, or any topic outside of volume calculation and measurement.

Start with the aquarium volume calculator hub to browse all 20 shapes, or use the aquarium shapes guide to identify your tank type. For reference data, the volume by size table and volume by brand table cover standard and manufacturer-specific sizes.