Square Footage Calculator
Add rooms/areas in feet, inches or metres and get total square footage.
Formula
Sq Ft = Σ (length × width)
How to use
- 1Pick your input unit: feet, inches or metres.
- 2Enter length and width for up to three rooms or sections.
- 3Leave unused rooms at 0.
- 4Read the total in both ft² and m², plus the rooms counted.
About this calculator
Nearly every home project quote starts with one number: how many square feet? Flooring, paint, tile, carpet, HVAC sizing and real-estate listings all lean on it. This tool adds up to three rectangular rooms at once and converts cleanly between feet, inches and metres, so you can turn measurements into a confident buying decision.
Formula explained
Each room: Area = Length × Width. Total = Σ areas. Conversions: inches ÷ 12 to feet, metres × 3.28084 to feet, and 1 m² = 10.7639 ft². Because area multiplies two lengths, unit slips get squared, so pick one unit and stay with it.
Worked example
Room 1 is 120 ft², room 2 is 154 ft², for a total of 274 ft² (about 25.5 m²). To buy flooring, add roughly 10% waste and order about 300 ft².
Tips & notes
- Add a waste allowance: about 10% for straight-lay, 15% for diagonal or herringbone, rounded up to full boxes.
- Split complex shapes into rectangles; triangular ends are base times height divided by two.
- Paint needs wall area (height times width of walls), not floor area, so use this tool for floor and ground area.
- If the total looks off, re-check your unit selection first, as that is the usual reason.