Free Aquarium & Fish Keeping Calculators

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Tank volume, substrate, heater, filter, lighting, and weight calculators.

Water change parameters, salt, CO2, fertilizer, ammonia, and alkalinity calculators.

Stocking levels, feeding amounts, compatibility, bio-load, and breeding tank calculators.

Setup costs, electricity, evaporation, UV sterilizers, air pumps, and maintenance schedulers.

Calculate aquarium volume in gallons for rectangular, cylindrical, bow-front, and hexagonal tanks.

Calculate pounds of substrate needed for your aquarium based on tank dimensions and desired depth.

Calculate the wattage of heater needed based on your tank size and temperature differential.

Calculate the required filter flow rate (GPH) based on your tank volume and fish type.

Calculate the total weight of a filled aquarium including water, substrate, and decorations.

Calculate resulting water parameters after a partial water change.

Calculate CO2 concentration from pH and KH, and determine target bubble rate.

Calculate the toxic ammonia (NH3) fraction from total ammonia, pH, and temperature.

Calculate how many fish your aquarium can hold using the inches-per-gallon rule with adjustments.

Calculate the right food amount and feeding frequency based on fish count and species type.