Tools

Calculators for the things people actually need to figure out. Live updating, no submit button, results stay local to your browser.

Aquariums

Tank volume
Rectangular, bowfront, cylindrical, hex, and custom shapes. Reports gallons (US and imperial) and liters.
Fish stocking calculator
Bioload, schooling minimums, and weekly water change estimates. Replacement for the ancient AqAdvisor.
Water change
How much water to swap to bring nitrate, TDS, or any dilutable parameter down to a target value.
Heater wattage
How many watts of heating you need. Quick rule-of-thumb mode or physics-based detailed mode for non-standard tanks and unusual rooms.
Substrate volume
Substrate volume for a tank footprint plus depth. Estimates bag counts for common aquasoil, sand, and gravel products.
Tank weight calculator
Total weight on your floor: water, glass, substrate, hardscape, and stand. For anyone worried about putting a tank upstairs.
Medication dosing
Calculate the right dose for common aquarium medications, with species warnings based on your stocking.
GH / KH remineralizer
How much remineralizer to add to RO or distilled water to hit a target GH (and KH if the product raises both).
Nutrient dosing
EI, EI-lite, PPS-Pro, and commercial liquid dosing for planted tanks. Reads your saved plant roster to suggest a method.
CO2 / pH / KH calculator
Estimate dissolved CO2 in your planted tank from pH and KH readings.
Aquarium lighting
PAR-at-substrate targets by plant tier. Enter your fixture PAR-at-surface and tank depth, see which plants will thrive.
Planted tank planner
Pick the plants you want to keep, get a substrate recommendation, water parameter range, light and CO2 requirements, and fish-compatibility warnings.

Hydroponics

Aquaponics

Solar