Square Footage Calculator
Enter every measurement Square Footage Calculator asks for, then press Calculate. The result stays blank while you are still typing.
Press Calculate after the entries are in.
What Square Footage is for
Square Footage Calculator is the page to open when you need square footage from measurements you already have. It belongs with the other construction calculators because that is the work this arithmetic supports. Type the entries first. The result stays hidden until you press Calculate, so a half-finished form never flashes a number you might mistake for the answer.
How to fill in this calculator
- Shape. Enter the value this part of the job needs. The choices include Rectangle, Square, Circle, Triangle.
- Length. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Width. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Diameter. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Side a. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Side b. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Side c. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Border Width. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Quantity. Enter the value this part of the job needs.
- Shape. Enter the value this part of the job needs. The choices include Rectangle, Square, Circle, Triangle.
- Length. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Width. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Diameter. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
- Side a. Enter the value this part of the job needs. The unit list on this field includes in, ft, yd, cm, m.
The form continues past those fields, 91 inputs in all. Extra rows are for a second area, a second board, or another piece of the same kind. Leave a row blank when you do not have that piece. Use Add another only when you do.
The formula in plain language
Area of a rectangle is length times width. A square uses one side twice. A circle is π times the radius squared. A triangle with three known sides uses Heron's formula: take the semi-perimeter, multiply the four terms, and take the square root. Add the pieces when a room is L-shaped, and multiply by the count when several identical areas repeat.
A worked example
A 12 foot by 14 foot room is 168 square feet, or 18.7 square yards. At $4.50 a square foot the flooring material is $756 before waste.
Area is the measurement under paint, tile, flooring, and a price per foot. This square footage result should agree with concrete calculator and area in square yards.
Mistakes that move the answer
- Measure to the outside of the area you will cover, then add waste separately instead of stretching the tape.
- Inches must be converted before they are multiplied, or a 6 inch width becomes a 6 foot width.
How to check the result
After Calculate shows the square footage result, redo the last operation with a pencil using the rounded figures on the screen. Matching that check means the inputs were read correctly. If you edit a label or a sentence in this HTML file, reload the page. The form and this article both live in the file, so the edit is what visitors will read.