Free tools
Purifier Calculators: Get a Number, Not a Sales Pitch
Every calculation on this site runs in your browser. Nothing is sent anywhere, no email address is required, and no result is gated behind a form — the tools exist to be used, not to harvest contact details.
Every tool also states its assumptions on screen. A calculator that hides its arithmetic is asking you to trust an output you cannot check, which is exactly the position a purifier salesperson puts you in. Where a figure is indicative rather than exact, we say so.
All calculators
- Water · Start hereTDS → purifier recommenderEnter your TDS reading, source and any contamination concern, and get the technology you actually need — including when the honest answer is that you do not need RO.Answers: Do I need RO, or is UV+UF enough?
- Air · Start hereRoom size → CADR calculatorRoom dimensions plus your city's typical AQI give you the minimum clean air delivery rate to shop for, adjusted for real Indian conditions rather than sealed test chambers.Answers: What size air purifier does this room need?
- Refrigerators · Start hereRefrigerator size calculatorHousehold size, shopping and cooking habits and the width of your kitchen gap give you the litre band that fits — sized on usable space rather than the gross figure on the sticker, with the annual electricity cost alongside it.Answers: How many litres of refrigerator do I need?
- WaterRO water wastage calculatorTurns the abstract 1:3 reject ratio into litres per year for your household, prices what that water is worth, and tells you whether your ratio is normal or a symptom.Answers: How much is my RO sending down the drain?
- Water & airAnnual running cost calculatorElectricity, filters, membrane, lamp and AMC in one figure — the number that separates two purifiers over five years, and the one nobody compares at the point of sale.Answers: What will this purifier cost me every year?
- B2BCommercial RO TCO calculatorFor societies, offices and factories: litres per day and input TDS give an indicative capex band, annual opex and the capex-versus-opex split to take into a budget meeting.Answers: What will a commercial RO plant cost to own?
Before you use any of these, measure something
For water, that means a digital TDS meter. It costs about ₹300, takes twenty seconds to use, and it is the single highest-value purchase in this entire category — because every subsequent decision, and every one of the water tools here, depends on a number you can only get by measuring. Measure the raw supply, in summer and in monsoon, and design around the higher reading.
For air, it means knowing your room's actual dimensions and your city's typical seasonal AQI, both of which take a minute to establish. If you can stretch to it, an air purifier with a numeric PM2.5 readout will teach you more about your own home in a week — cooking spikes, the effect of an open window, the difference between 6 a.m. and 2 p.m. — than any article can.
Want us to run the numbers with you?
Tell us your city, your water or your room, and we will give you a straight recommendation — including when the honest answer is that you do not need to spend much at all.