Water Treatment Calculators
Every calculator on the site, grouped by the job. Each one shows the formula and the steps with your numbers, lets you mix metric and US units, keeps its inputs in the link so you can share or repeat a result, and prints a dated record. Nothing you type is uploaded.
Volume
- Tank volume calculator — total and filled volume of cylindrical, rectangular, capsule, cone-bottom, oval and spherical tanks, with a dip chart.
- Pool volume calculator — gallons and litres in rectangular, round, oval, kidney and L-shaped pools.
- Aquarium volume calculator — fish tank gallons and litres for common tank shapes, and the water weight.
Pool water chemistry
- Pool salt calculator — salt to add for a target salinity, in pounds, kilograms and bags.
- Pool chlorine calculator — how much liquid chlorine, bleach or granular product raises free chlorine.
- Langelier saturation index calculator — LSI and Ryznar index: is the water scaling or corrosive?
Water treatment
- Water hardness converter — ppm, grains per gallon, °dH, °fH and mmol/L, with a hardness chart.
- Water softener size calculator — grains per day and the softener capacity for your household.
- Chlorine dosage calculator — chlorine feed rate, tank and well disinfection, and breakpoint chlorination.
Water supply and wastewater
- Water usage calculator — daily, monthly and yearly household water use by fixture.
- Rainwater harvesting calculator — rain collected from a roof and the cistern size for your demand.
- Septic tank size calculator — tank size from bedrooms or daily flow.
All results are estimates. Follow product labels and local regulations, and test the water after any treatment. You may use the results in commercial work.