Square Footage Calculator

Calculate the square footage and area of various shapes like rectangles, circles, triangles, and more to estimate materials or cost.

Select Shape

Length

Width

Quantity

Price (Optional)

Area planning

What Is a Square Footage Calculator?

A square footage calculator finds the area of a flat surface. It is commonly used for rooms, floors, walls, land, patios, flooring, paint, tile, and renovation estimates.

Square footage is area, not length. A 12 ft by 10 ft room covers 120 ft^2 because the length and width are multiplied together.

How to use it

How to Use This Square Footage Calculator

Pick the geometry that matches your space, then enter the measurements in the units you already have.

1
Select the shape
Choose rectangle, border, circle, ring, triangle, trapezoid, sector, or parallelogram.
2
Enter the measurements
Use the dimensions requested by that shape, such as length and width, diameter, radius, base and height, or side lengths.
3
Choose the units
The calculator converts feet, meters, yards, inches, miles, kilometers, and centimeters into one area calculation.
4
Add quantity and price if needed
Use quantity for repeated areas and price per unit area for material or project cost estimates.

Common projects

Where Square Footage Estimates Help

A clean area estimate makes it easier to compare material quantities, pricing, and project scope.

Flooring and tile: Estimate material coverage for carpet, hardwood, laminate, vinyl, tile, or underlayment.
Paint and wall projects: Measure wall or ceiling area before estimating paint, wallpaper, drywall, or paneling.
Land and outdoor planning: Measure patios, lawns, garden beds, pavers, concrete pads, or landscaping zones.
Real estate and renovation: Compare room size, floor area, usable area, and project cost across multiple spaces.

The math

Square Footage and Area Formulas

The calculator supports common flat shapes. Each formula returns area before quantity and optional price are applied.

Basic rectangular area formula

A = L \times W

This is the standard formula for most rectangular rooms, floors, ceilings, and walls.

Shape	Formula	Best use
Rectangle	$A = L \times W$	Rooms, floors, walls, patios, and simple rectangular areas.
Rectangle border	$A = LW - (L - 2b)(W - 2b)$	Border strips where the center opening is removed.
Circle	$A = \pi r^2$	Circular lawns, rugs, tables, pads, or round surfaces.
Ring	$A = \pi (R^2 - r^2)$	Donut-shaped areas with an outside and inside radius.
Triangle from sides	$A = \sqrt{s(s-a)(s-b)(s-c)}$	Use Heron's formula when all three side lengths are known.
Triangle from base and height	$A = \frac{bh}{2}$	Triangular sections where the perpendicular height is known.
Trapezoid	$A = \frac{(b_1 + b_2)h}{2}$	Four-sided areas with two parallel sides.
Sector	$A = \frac{\theta}{360^\circ}\pi r^2$	A slice of a circle measured by radius and angle.
Parallelogram	$A = bh$	Slanted rectangles where base and perpendicular height are known.

Units and cost

Conversions, Quantity, and Price

After area is calculated, the result can be converted into other square units and multiplied by quantity or price per unit area.

Conversion	Formula
Square feet to square yards	$\mathrm{yd}^2 = \frac{\mathrm{ft}^2}{9}$
Square feet to square meters	$\mathrm{m}^2 = \mathrm{ft}^2 \times 0.092903$
Square meters to square feet	$\mathrm{ft}^2 = \mathrm{m}^2 \times 10.7639$
Square feet to acres	$\mathrm{acres} = \frac{\mathrm{ft}^2}{43560}$

Cost estimate

\text{Total cost} = \text{total area} \times \text{price per unit area}

Use the same pricing unit you select in the calculator, such as per square foot or per square meter.

Material planning

Waste Allowance for Flooring and Tile

The calculator gives the measured area. Material purchases often need a practical allowance beyond that measurement.

Flooring, tile, carpet, hardwood, laminate, and paver projects commonly need extra material for cuts, damaged pieces, pattern matching, and fitting around corners.

Common Square Footage Mistakes

These issues can make an area or material estimate inaccurate.

Mixing linear and square units

Linear feet measure length. Square feet measure area, so material coverage needs length times width.

Multiplying different units

Convert inches, feet, yards, or meters before multiplying dimensions together.

Ignoring repeated areas

If a shape occurs multiple times, multiply one area by the quantity before estimating cost.

Skipping waste allowance

Flooring, tile, carpet, and paver projects often need extra material for cuts, patterns, and fitting.

Using diameter as radius

Circle formulas use radius. If the calculator asks for diameter, it converts it internally.

Frequently Asked Questions

It calculates the area of a room, floor, wall, land section, or shape and converts that area into common square units.

For a rectangle, multiply length by width. If both measurements are in feet, the result is square feet.

Calculate each room separately, then add the areas together. Quantity can also be used when the same shape repeats.

Multiply total area by the price per unit area, such as dollars per square foot.

Yes, many flooring and tile projects need extra material for cuts, fitting, mistakes, and pattern matching.

Square feet measure surface area. Cubic feet measure volume, which also includes height or depth.

💡

💡 Have an Idea?

Can't find the calculator you're looking for or want to suggest improvements? Let us know and we'll build it for you!