How to measure square footage of a room, wall or lot

Start with a rectangle

Area is length times width. For a plain rectangular room, measure both sides and multiply. Use feet and you get square feet. Use metres and you get square metres.

Split odd shapes into rectangles

Few rooms are perfect rectangles. Draw the shape in your notebook and cut it into rectangles. Work out each, then add them up.

1. Sketch the room and mark each straight side.
2. Draw lines to split it into rectangles. An L-shape becomes two.
3. Measure and multiply each rectangle.
4. Add the areas together.
5. For a space to leave out, such as a built-in, measure it and subtract it.

Walls and lots

For a wall, area is length times height. For a lot, use the same method: split the shape and add. A triangle is half of its base times its height.

If your plans are in metres and your supplier sells by the square foot, change one to the other. One metre is about 3.28 feet, and one square metre is about 10.76 square feet.

Worked example: an L-shaped room (made-up figures)

One part of the room is 14 feet by 12 feet, which is 168 square feet. The other part is 8 feet by 6 feet, which is 48 square feet. The total is 216 square feet.

If you price flooring at $4 a square foot, the labour line is $864 before Tax A and Tax B. Add the tax lines you take from the official source on top.

Habits that save rework

A few habits make the numbers dependable, and they cost nothing.

• Measure twice, and write each number down as you go.
• Measure to the same point each time, such as finished wall to finished wall.
• Note which unit you used on the page.
• Keep the sketch with the job.

When a customer asks why the price changed, a sketch with numbers on it ends the argument quickly. It also lets you reuse the measurements if the customer calls back to add a room.

Check your figures with the square footage calculator

Type the same figures into the square footage calculator if you want a second check. It is free to start, you type every figure yourself, and nothing is sent. Then put the area into your quote.

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