Need to know how much floor, lawn or land you are working with? This area calculator works out the area of any rectangle, such as a room, a yard or a lot. Enter the length and width in feet and it shows the result in square feet, square yards and square metres.
It also has an optional field for how many areas of the same size you have. That is useful when you are planning several identical rooms or sections and want the combined total in one step.
How to use the area calculator
- Measure the length of the rectangle in feet. If you have inches, convert them to a decimal part of a foot before you enter them.
- Measure the width of the same rectangle in feet, using the same corners and the same straight line.
- Type the length into the Length (ft) box and the width into the Width (ft) box.
- If you have more than one area of this size, enter the count in the optional box. Leave it as 1 for a single area.
- Read the three results: area in square feet, square yards and square metres. Use whichever unit matches what you plan to buy or order.
The formula
- Square feet = length × width × how many
- Square yards = square feet ÷ 9
- Square metres = square feet × 0.09290304 (0.3048 × 0.3048)
Worked example
The figures below are made up to show the maths. They are not current prices, rates or product figures.
| Length | 20 ft |
|---|---|
| Width | 15 ft |
| How many areas this size | 1 |
- Area 300.0 sq ft
- Area 33.33 sq yd
- Area 27.87 sq m
Tips for an accurate answer
- Measure the longest straight edges of the room or plot, and check that the corners are square before you trust the width.
- Write down your measurements before you enter them, so you can check for a typing slip if the result looks unexpected.
- If the space is not a rectangle, split it into rectangles, work out each area separately, then add the results together.
- Use a tape measure held level and taut for indoor rooms, and remember that wall thickness or trim can change what you consider the usable length.
- Keep at least one decimal place in your measurements when you can, since rounding early can shift the final area.
Questions people ask
What does this area calculator measure?
It measures the area of a rectangle, which covers many rooms, yards and lots. You enter a length and a width, and the calculator multiplies them to give the area.
Can I use inches in the length or width?
The calculator is set up for feet. If your measurement includes inches, convert the inches to a fraction of a foot first and add it to the whole feet before you enter the value.
What is the difference between square feet and square yards?
Square feet and square yards both measure area, but a square yard is a larger unit. The calculator shows the square yard result so you can compare it with materials sold by the yard.
What does the optional count field do?
If you have several areas that are the same size, enter how many there are. The calculator then gives the total area for all of them, which is helpful when planning repeated sections.
Will this calculator work for an irregular shape?
Not directly, because it is built for rectangles. For an irregular shape, divide the space into smaller rectangles, calculate each one, and add the results together.
Sources
- 1 foot = 0.3048 metre exactly, so 1 inch (a twelfth of a foot) = 2.54 cm. Source: NIST, Revised unit conversion factors (the international foot).
- 1 yard = 0.9144 metre (3 feet). Source: NIST, NIST Guide to the SI, Appendix B.8: Factors for units listed alphabetically.
An estimate from the numbers you enter, worked out with the formula shown. Check quantities with your supplier before you order. Formulas and examples reviewed 24 Oct 2026. Read the disclaimer