Free area calculator

Square Footage Calculator

Square Footage Calculator: Find square footage, square yards, square meters, or acres for a building, home, garden, or job site. Pick

Room Dimensions

Material Waste FactorOPTIONAL

Estimate Material CostOPTIONAL

Calculation Results

More square footage calculators

Pick a calculator for rooms, shapes, materials, outdoor areas, or unit conversions.

Room Calculator → House Calculator → Bedroom Calculator → Bathroom Calculator → Kitchen Calculator → Multiple Rooms → Rectangle Calculator → Triangle Calculator → Circle Calculator → Trapezoid Calculator → Regular Polygon Calculator → Irregular Shape → Odd Shape → Uneven Sides → Flooring Calculator → Tile Calculator → Paint Calculator → Concrete Calculator → Insulation Calculator → Lawn Calculator → Yard Calculator → Landscaping Calculator → Pool Calculator → Garage Calculator → Roof Calculator → Wall Calculator → Feet & Inches → Inches Calculator → Height Width Length → Sq Ft to Acres → Cubic Yards Calculator →

What is a square foot?

1 ft (12 in) 1 ft 1 ft² = 144 in²

A square foot (sq ft) is a unit of two-dimensional area. One square foot is a square that is 1 foot (12 inches) on each side. It is the usual unit for room size, property area, and material coverage for flooring, paint, and landscaping.

How to calculate square footage

12 ft 10 ft Area 120 ft²

Measure the length and width of your space in feet, then multiply those two numbers. The product is the area in square feet.

Example calculation

A room is 12 feet long and 10 feet wide. Multiply 12 by 10 to get 120. That room has 120 square feet.

Basic formula for area

L × W = Area ft²

The basic area formula is Length × Width. Measure length and width in the same unit before you multiply.

Basic length conversion

These three length conversions show up often in area work:

  • Inches to feet: divide inches by 12.
  • Yards to feet: multiply yards by 3.
  • Meters to feet: multiply meters by 3.28084.

Area conversion

1,000 ft² Square Feet 144,000 in² 111.11 yd² 92.90 m² 0.023 acres

These four area conversions are common in construction estimates:

  • Square inches to square feet: divide by 144.
  • Square yards to square feet: multiply by 9.
  • Square meters to square feet: multiply by 10.7639.
  • Acres to square feet: multiply by 43,560.

Use the Area Conversion Calculator above to run these conversions for you.

Area formulas for different shapes

Square Rectangle Circle Triangle Trapezoid L-Room Wall Annulus

The Square Footage Calculator supports 13 geometric shapes. The formulas below are the ones used for each shape.

Square shape

Square Side (a) Side (a)

Calculate square footage of a square

Formula: Side Length × Side Length. Measure one side and multiply it by itself.

Rectangle shape

Rectangle Length (l) Width (w)

Calculate square footage of a rectangle

Formula: Length × Width. Measure the long side and the short side, then multiply.

Rectangle border shape

Rectangle Border

Calculate square footage of a rectangle border

Formula: Total Area (Outer Length × Outer Width) minus Inner Area (Inner Length × Inner Width). Find the outer rectangle area, then subtract the inner rectangle.

Wall and window shape

Wall with Window

Calculate square footage of a wall minus a window

Formula: Wall Area (Wall Height × Wall Width) minus Window Area (Window Height × Window Width). That gives the paint or drywall area you need.

Cathedral wall

Cathedral Wall

Calculate square footage of a cathedral wall (right trapezoid)

Formula: ½ × Base Width × (Left Wall Height + Right Wall Height). Use this for walls under a sloped ceiling.

Circle shape

r Circle

Calculate square footage of a circle

Formula: π × Radius². Measure from the center to the edge (radius), square it, and multiply by 3.14159.

Circle border shape

Annulus / Border

Calculate square footage of a circle border

Formula: π × (Outer Radius²) minus π × (Inner Radius²). Subtract the inner circle area from the outer circle area.

Annulus shape

Annulus / Border

Calculate square footage of an annulus

Formula: π × (Outer Radius² - Inner Radius²). Annulus is the math term for a ring or circle border.

Triangle shape

Base (b) Triangle

Calculate square footage of a triangle

Formula (Heron): √[s(s-a)(s-b)(s-c)], where s is half the perimeter. Measure all 3 sides when you do not know the height.

Triangle shape (base and height)

h Base (b) Triangle

Calculate square footage of a triangle using base and height

Formula: ½ × Base × Height. Measure the bottom length and the straight vertical height.

Trapezoid shape

h Top (a) Base (b) Trapezoid

Calculate square footage of a trapezoid

Formula: ½ × (Base A + Base B) × Height. Add the parallel sides, multiply by the straight height, and divide by 2.

Sector

θ r Sector

Formula: ½ × Radius² × Angle (in radians). This finds the area of a wedge of a circle.

Parallelogram

h Base (b) Parallelogram

Formula: Base × Height. Multiply the bottom length by the vertical height.

Calculations for L-shaped rooms or areas

A₁ = 180 × 80 A₂ = 100 × 100 10 ft Total Area A₁ + A₂

Split an L-shaped or irregular area into two rectangles. Calculate each with Length × Width, then add the two results.

Example calculation

Section A is 10 ft by 5 ft (50 sq ft). Section B is 6 ft by 4 ft (24 sq ft). The total is 74 square feet.

Calculating square footage for walls

Wall Width Height W × H − windows − doors

Measure wall width and height in feet. Multiply width by height. Subtract doors or windows to get the paint area you need.

Calculating the square footage of a house or property

Living Room 250 ft² Kitchen 180 ft² Bedroom 200 ft² Bathroom 50 ft²

Measure length and width of each rectangular room. Calculate each room, then add the totals. Unfinished basements and garages are usually left out of standard real estate square footage.

Adding surplus for materials

Usable material Waste (~10%)

Most projects need 5% to 15% more material than the exact area to cover cuts, mistakes, and waste. Use the material waste toggle in the calculator to add that surplus.

Waste percentages by material type

Three common waste ranges for construction materials:

  • Hardwood flooring: add 5% for standard rooms, 10% for diagonal layouts.
  • Tile: add 10% to 15% for complex patterns and breakage.
  • Paint: add 10% for spillage and touch-ups.

Calculating cost per square foot

Area 120 ft² × Price $3/ft² = Total $360

Divide total project cost by total square footage. Example: a $1,000 project covering 200 sq ft costs $5 per square foot.

Painting a house

Measure height and width of exterior walls. Subtract windows and doors. Multiply the remaining square footage by the paint coverage rate (often about 350 sq ft per gallon).

Flooring installation

Find the floor area in square feet and add about 10% for waste. Multiply that total by the price per square foot of your flooring.

Building a home

Multiply the floor plan area by the regional building cost per square foot to rough out total construction cost.

Calculate cost of materials

Tile $2/ft² Wood $5/ft² Carpet $7/ft² Marble $12/ft²

Turn on Material Cost in the calculator. Enter price per unit and currency. The tool multiplies final project area (including waste) by that price.

How to use the Square Footage Calculator

1 Shape 2 Dims 3 Result Select Shape Enter Dimensions Get Area + Cost

Pick your shape from the dropdown. Enter length, width, or the other fields the shape needs. Set units as you like. The calculator returns square footage automatically.

How to calculate square footage pricing

Get total area, add your waste factor, then multiply final square footage by the contractor or material rate per square foot.

Calculate square footage (sq ft) from other units

Enter measurements in yards, meters, or inches. The calculator converts the inputs and shows the result in square feet.

How do I convert square meters to square feet?

Multiply square meters by 10.7639 to get square feet.

How do I convert acres to sq ft?

Multiply acres by 43,560 to get square feet.

A few notes on square footage

Accurate area numbers help you avoid short material orders and blown budgets. For bulk materials like mulch or gravel, calculate area first, then convert volume to cubic yards.

How It Works

1

Select Shape

Choose the shape that matches your space.

2

Enter Dimensions

Enter measurements in any unit. Add quantity, waste factor, and material price if you need them.

3

Get Results

See area in ft², in², yd², m², and acres, plus a cost estimate when you enter a price.

Frequently Asked Questions

Pick the shape from the dropdown: Room, Rectangle, Circle, Triangle (Heron's or base times height), Trapezoid, Cathedral Wall, Annulus, and others. Enter measurements and click Calculate. The calculator runs the right formula and shows square feet, square inches, square yards, square meters, and acres.
Yes. Every calculation shows five area units at once: square feet (ft²), square inches (in²), square yards (yd²), square meters (m²), and acres. You do not need a separate conversion step.
Measure each room, wall, or area in your project. Enter numbers in the calculator, pick the shape, and click Calculate. Add a waste percentage (5 to 15% depending on material), enter cost per unit area, and the calculator totals material quantity and cost.
The waste factor increases total area by a percentage to cover material lost in cutting and installation. Use 5 to 10% for standard flooring and carpet. Use 10 to 15% for diagonal tile or complex layouts. Enter the percentage in Material Waste Factor and the calculator adjusts total area.
Yes. Estimate area and material needs for gardens, walkways, patios, and lawns. Pick the shape that fits your space, enter dimensions, and get total square footage. Enter a material price to figure costs for sod, mulch, pavers, or gravel.
Divide square feet by 10.7639 to get square meters. Example: 500 ft² ÷ 10.7639 = 46.45 m². The calculator shows the m² equivalent on every run.
10 ft × 10 ft = 100 ft², which equals 9.29 m². A 10-by-10-foot room (3.048 m × 3.048 m) has about 9.29 square meters of floor area.
The formula is ½ × Base Width × (Left Height + Right Height). Left and right heights differ because the ceiling slopes. The shape is a right trapezoid. Enter base width and both wall heights for area in square feet.
Yes. Each input has its own unit selector: feet, inches, yards, meters, or centimeters. The calculator converts internally before computing area. Length in meters and width in feet still gives an accurate result.
Both use π × (R² − r²). Circle border and annulus both find the area between two concentric circles. The calculator lists both names because some people search "circle border" and others search "annulus." The result is the same.
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