Irregular Area Calculator (Square Feet & Square Meters)
Break an odd-shaped room or lot into rectangles and right triangles, enter each piece, and add them into one total in square feet and square meters.
How it works
Rooms and lots rarely come as a single clean rectangle, but almost any flat shape can be carved into rectangles and right triangles. That is the trick this calculator uses: you split the space into simple pieces, measure each one, and it adds the areas into a single total. A rectangle's area is length times width; a right triangle's area is half its base times its height. Sum the pieces and you have the whole.
Add a row for each piece, choose rectangle or triangle, and type its two dimensions. An L-shaped room becomes two rectangles; a lot with a clipped corner becomes a rectangle plus a triangle. The running total updates as you go, in square feet with the square-meter equivalent beside it. For example, a 12 ft by 10 ft rectangle plus a right triangle with a 6 ft base and 4 ft height totals 120 + 12 = 132 square feet. Switch the toggle to enter everything in meters. Measure carefully where pieces meet so you neither double-count nor leave a gap.
Right triangle base 6 ft, height 4 ft = 12 sq ft
Total = 132 sq ft (12.26 sq m)