Aquarium Calculator

Aquarium Calculator is a set of aquarium planning tools built around real tank decisions. It focuses on helping hobbyists work from actual measurements and setup needs rather than tank labels, generic rules of thumb, or forum guesses.

The site offers 11 calculators covering volume, substrate, stocking, water changes, salt mix, glass safety, hardware, setup cost, light, filter and flow, heater, and weight. Its descriptions say the calculators can provide exact answers for volume, stocking, filtration, heating, substrate, and safety. Several tools are described in more detail: the Volume Calculator gives net volume for conditioners, mixes, heaters, filters, and stocking; the Substrate Calculator estimates how much gravel, sand, or aquasoil is needed with displacement-aware results; the Stocking Calculator factors in bioload, adult size, and tank volume; and the Heater Calculator matches wattage to room temperature and tank size with a safety margin. Other tools cover setup budgeting, filter turnover, panel safety and bowing risk, total system weight, planted and reef lighting, salt mix amounts for marine tanks, and water changes aimed at a nitrate target.

It also includes saved tank context so dimensions and results can carry across tools, and it offers a personalized shopping feature that ranks gear based on entered tank numbers. The page notes support for all tank shapes, including rectangular, bowfront, cylinder, and corner tanks. It also supports imperial and metric units, is mobile friendly, and is available in English, Japanese, Hindi, Spanish, and German.

Aquarium Calculator is described as free forever, with no signup, paywalls, or hidden fees. Shopping links may be affiliate-supported. The page presents it as a tool for aquarium hobbyists and for people making setup, stocking, dosing, and upgrade decisions from real tank measurements.