How do I calculate square footage?

Multiply the length by the width, both measured in feet. For example, a room 12 ft long and 10 ft wide is 12 × 10 = 120 square feet.

How do I handle an irregularly shaped room?

Divide the space into rectangular sections, calculate the square footage of each section separately, then add the results together for the total area.

How do I convert square feet to square yards?

Divide the square footage by 9, since one square yard equals 9 square feet. Carpet is often priced per square yard.

What if my measurements are in inches?

Divide each measurement by 12 to convert inches to feet before entering them, or measure directly in feet for the most accurate result.

Square Footage Calculator

What the Square Footage Calculator Does

This square footage calculator finds the area of a space in square feet from a simple length and width measurement. Enter the two dimensions and it returns the floor area, which is the number you need for most real-world projects.

It is built for renters and buyers comparing listings, homeowners planning a renovation, and anyone shopping for materials sold by area. Flooring, carpet, tile, paint, sod, and concrete are all priced and ordered by the square foot, so an accurate area figure keeps your budget and your purchase quantity correct.

How It Works: The Square Footage Formula

For any rectangle or square, area is length multiplied by width. When both measurements are in feet, the result is automatically in square feet:

area = length (ft) x width (ft)

If you measure in inches instead, divide each measurement by 12 to convert it to feet before multiplying, since there are 12 inches in a foot. To convert square feet to square yards (common for carpet), divide the square footage by 9, because one square yard equals 3 ft x 3 ft.

Worked Example with Real Numbers

Suppose a bedroom measures 12 feet long by 10 feet wide. The area is 12 x 10 = 120 square feet.

Now imagine the floor is partly mixed units: 12 feet 6 inches by 10 feet. Convert 6 inches to feet (6 / 12 = 0.5 ft), giving a length of 12.5 feet. The area becomes 12.5 x 10 = 125 square feet.

If you were buying carpet for that 125 sq ft room, dividing by 9 gives about 13.9 square yards.

Measuring Irregular or L-Shaped Rooms

Rooms are rarely a perfect rectangle. The reliable method is to split the floor plan into separate rectangles, calculate each one, and add the results.

For an L-shaped room, draw a line to divide it into two rectangles. If one section is 10 ft x 8 ft (80 sq ft) and the other is 6 ft x 4 ft (24 sq ft), the total is 80 + 24 = 104 square feet. Subtract the area of any fixed features you will not be covering, such as a kitchen island or a built-in closet bump-out.

Tips and Common Mistakes

A few habits keep your numbers accurate and your material order right:

Measure twice at floor level, not along a slanted wall, and round measurements to the nearest inch.
Keep units consistent. Mixing feet and inches without converting is the most common error.
Do not confuse square feet with linear feet. Square footage measures area; linear feet measure a single straight distance.
Add waste when buying materials. Most installers add 5 to 10 percent for cuts, with more for diagonal or patterned layouts.
For irregular shapes, verify your split rectangles cover the whole floor with no gaps or overlaps.

Factors That Affect the Result

The dimensions you feed in are only as good as your measurements, so wall bows, baseboards, and out-of-square corners can all shift the total. For listings and appraisals, definitions of what counts as livable area can differ, so always check whether closets, hallways, or finished basements are included.

When ordering by area, remember that the calculator gives the exact floor area, not the amount of product to buy. Add your waste percentage and round up to the nearest box or roll so you finish the job without a second trip.