Square Feet Calculator

Calculate square feet from length and width, multiple areas, or known area conversions. Estimate square yards, square meters, acres, material quantity, waste, and project cost.

Calculate Square Feet

Square Feet = Length × Width. Square Feet With Waste = Net Square Feet × (1 + Waste Percentage).
Your result will appear here.

How the square feet calculator works

Length and width mode:
The calculator multiplies length by width and converts the result into square feet.

Multiple areas mode:
The calculator multiplies one area by the number of same-size areas.

Known area mode:
The calculator converts your known area into square feet, square yards, square meters, acres, and more.

Circular area mode:
The calculator uses diameter to estimate circular square footage and perimeter.

Why use a square feet calculator?

A square feet calculator helps estimate area for rooms, floors, walls, ceilings, yards, patios, garages, decks, roofs, concrete slabs, paint, tile, carpet, and other projects.

It can help calculate square feet, square yards, square meters, acres, perimeter, material quantity, waste, material cost, labor cost, and estimated total project cost.

What your result means

Your result shows net square footage, square footage with waste, square yards, square meters, acres, perimeter, material units, material cost, labor cost, and estimated total cost based on your inputs.

Square feet formulas

Frequently asked questions

How do I calculate square feet?

Multiply length by width. For example, a 12 foot by 10 foot room has 120 square feet.

How many square feet are in a square yard?

One square yard equals 9 square feet.

How many square feet are in an acre?

One acre equals 43,560 square feet.

How much extra square footage should I add for waste?

Many projects use 5% to 15% extra for waste, cuts, overlap, mistakes, and irregular shapes. Some materials may need more.

Is this square feet calculator exact?

No. It is an estimate. Actual square footage and material needs can vary by shape, cuts, obstacles, openings, slopes, overlap, material size, waste, and installation method.