Some of the most common buying mistakes at home are sizing mistakes: an air purifier too small for the room, a king bed that leaves no space to walk, a living room lit like a hallway. These free calculators help you size things correctly before you buy. Each one explains its method and the industry guidance it follows.
Air Purifier Room Size (CADR) CalculatorThe CADR you need for your room, and air changes per hour for any purifier.Mattress Size Chart & Room Fit CalculatorEvery US mattress size, and which ones fit your bedroom with room to walk.How Many Lumens Do I Need? Room Lighting CalculatorLumens and number of LED bulbs for any room, from bedroom to workshop.How Many Storage Bins Fit on a Shelf?How many totes fit — and which way to turn them — on any shelf.Air Purifier Running Cost CalculatorElectricity plus filters — the true yearly cost of any purifier.Mattress Firmness & Pillow Loft FinderFirmness, mattress type and pillow height for how you sleep.What Size Dehumidifier Do I Need? (Pints Calculator)The right pint capacity for your room size and dampness level.Paint Coverage Calculator (Gallons + Primer)Gallons of paint and primer for your walls, ceiling and coats.Vacuum Finder Quiz: Which Vacuum Fits Your Home?Four questions — upright, stick, robot or canister for your home?
Measure once, buy right
All three tools need the same thing — your room’s length and width (and ceiling height for the air purifier). Grab a tape measure, note the numbers, and run them through each calculator. Then compare the result with the specs on the product page: CADR for purifiers, mattress dimensions for beds and lumens for bulbs.