Room Size Calculator
Enter your room's length and width to calculate the floor area in m² and ft². Add ceiling height for wall area and paint estimates.
Unit
How to calculate the square footage of a room
Measure the length and width of the room in feet using a tape measure, then multiply length × width to get the area in square feet. For example, a room that's 10 feet long and 12 feet wide is 120 square feet (10 × 12 = 120).
For an L-shaped room or one with alcoves, split the floor plan into two or more rectangles, calculate each section's square footage separately, then add the totals together. The calculator above does this math for you — just enter length and width, and add ceiling height if you need a wall-area estimate for paint or wallpaper.
Frequently asked questions
How do I calculate the square footage of a room?
Measure the room's length and width in feet, then multiply length × width. A room that's 10 feet by 12 feet is 120 square feet. For an L-shaped or irregular room, split it into rectangles, calculate each separately, then add the totals together.
How do I find the square footage of a room without a tape measure?
Use the calculator above with an estimate, or pace it out: an average adult stride is about 2.5 feet. Count strides across the length and width, multiply by 2.5, then multiply those two numbers together for a rough square footage.
How do I measure square feet for flooring, tile, or paint?
Calculate the room's square footage first (length × width), then add 10% extra to cover cuts, waste, and mistakes — most flooring and tile suppliers recommend this buffer. For paint, you'll also need wall height; use the ceiling height field above to get a wall-area estimate.
What's the difference between square feet and square meters?
1 square meter equals about 10.76 square feet. This calculator converts between both automatically — enter your measurements in either feet or meters and get results in the other unit instantly.
Ready to redesign the room you just measured?
Design with AI