Square Footage & Area Calculator
Calculate rectangular area and estimate material quantity with waste allowance. Your work stays on this device whenever possible.
How to use Square Footage & Area Calculator
- Keep Calculation Mode on "Multi-Room List" and type one room per line in the Rooms box as Room Name, Length, Width.
- Choose Measurement Units: feet, inches, meters or yards; the answer is then converted to the other units.
- Set a Waste Factor Allowance from 0% up to 20% for cuts and mistakes, for example 10% for tile or wood.
- Enter Material Price ($/sq unit) and Box Coverage (sq units per box) to get a cost estimate and box count.
- Press "Calculate Square Footage" and read the net area, the waste-adjusted area and the room breakdown.
Worked example
Enter three rooms in feet: "Bedroom, 12, 11", "Den, 10, 9" and "Closet, 6, 4". Areas are 132, 90 and 24, so net area is 246.00 sq ft (22.85 sq m). At 10% waste that becomes 270.60 sq ft. With price 4.20 per sq ft, cost is 1,136.52, and with 22 sq ft per box you need 13 boxes.
When to use this tool
- Ordering flooring for several rooms with a cutting allowance.
- Converting a room size in meters to square feet for a rental listing.
- Estimating paint or tile cost from a list of room dimensions.
Important limitations
Calculations provide geometric planar area. Diagonal tile installations or herringbone patterns typically require a higher 15-20% waste allowance to cover custom corner cuts.
Frequently asked questions
How do the single-shape modes work?
Rectangle, circle and triangle modes read numbers from the same Rooms text box. Enter length and width as "20, 15", one radius for a circle, or base and height as "10, 8" for a triangle.
Is the waste factor applied to cost and boxes?
Yes. Net area is multiplied by one plus the waste percentage, and both the material cost and the number of boxes come from that larger figure, rounded up to whole boxes.
Do box coverage and price use the chosen units?
Yes. If you select meters, price and box coverage must be per square meter. The tool does not convert them, so mixing units will give a wrong cost.
What happens to malformed lines?
A row needs a name and at least a length; a missing width counts as zero, giving zero area for that room. Blank lines are skipped, and the tool errors if the total area is not positive.
Does it subtract closets, doors or fixtures?
No. Each room is a plain length times width rectangle. For L-shaped rooms, list the two rectangles as separate lines and add them together; cut-outs must be subtracted by hand.