Pick one. Type your numbers. Get an answer. Each calculator runs in your browser - no sign-up, no ads, no cookie-wall.
Interior L × W × H, minus substrate. Returns net litres, US gallons, surface area and a sensible glass thickness.
Grams of GH+ and KH+ to remineralise RO/DI for a target hardness and TDS.
Dry-salt dosing for KNO₃, KH₂PO₄ and K₂SO₄. EI, EI Low, PPS-Pro or custom.
Dissolved CO₂ in mg/L from pH and KH, with temperature compensation.
Most of aquarium-keeping is patience. The bits that aren't patience are usually arithmetic – tank volume for stocking and dosing, water-change recipes, weekly fertilizer doses, dissolved CO₂ from pH/KH. These four cover roughly 90%% of what hobbyists actually compute. Everything else is judgement.
Save calculations to a tank and stop retyping. Free forever.