Things You'll Need
Pencil or chalk
If you're thinking about replacing your countertop, you'll have to calculate the square footage of the surface to estimate on how much the project will cost. All countertop materials are sold by the square foot, so once you have a number you can shop around to find the countertop you like best. As you measure, remember not to add areas the countertop won't cover, such as an oven range, into your figure, but keep places where parts of the countertop will be cut away, such as where a sink goes, in the measurement.
Divide your countertop into runs or rectangular boxes. Use a straightedge to draw a line to mark off the edges of each box with a pencil or a piece of chalk. Do not include areas where the countertop will not cover, such as oven ranges, in your boxes.
Measure the width and length of each box or rectangle. Write down the figures for each box on a piece of paper.
Multiply the width of each box times its length. This will give you the area or square footage of each separate box or rectangle you created.
Add the area or the square footage of all the boxes together. This is the area of square footage of your countertop.
Erase or wipe the chalk lines from your counter.
Always measure at least three times to make sure all your measurements are correct.