AlienCalc — Real tools, slightly extraterrestrial

Surface Area Calculator (m²)

Quickly calculate the surface area of a room, wall, or floor in square meters. Simply enter the length and width to get an instant result. Perfect for estimating your construction material, paint, or tile needs.

Enter the length in meters
Enter the width in meters

Calculated surface area

The result corresponds to the area of the rectangular zone defined by the length and width you entered.

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How to calculate surface area in m²?

  • Rectangular room – Multiply length by width. A 5 m × 3 m room = 15 m².
  • L-shaped room – Break the room into two rectangles, calculate each surface separately, then add them together.
  • Wall surface – Multiply the wall length by its height. Then subtract openings (doors, windows).

Practical tips

When purchasing materials (paint, tiles, flooring), always add a 5 to 10% margin for cuts and waste. Always measure at the widest point of the room if the walls are not perfectly parallel.