Use this free square footage calculator to
measure any room, floor, garden, roof, or warehouse in seconds. Enter your
dimensions, pick a shape — rectangle, circle, triangle, or trapezoid — and
calculate area accurately in feet, inches, yards, meters, or centimeters,
plus get an estimate of the total cost for flooring, tile, carpet, or
concrete. Built to save time, get a precise quantity of materials, and meet
any project requirement.
Quick answer: To use a square footage calculator, measure the
length and width of your space in feet, multiply them together, and you
have the area in square feet (ft²). For a room that is 12 ft long and 10 ft
wide, the total square footage is 120 sq ft. For circles use π × r²,
for triangles use (base × height) ÷ 2, and for trapezoids use ((base 1 +
base 2) ÷ 2) × height.
What This Square Footage Calculator Does
A square footage tool turns a length and width measurement into a total
area expressed in square feet, square meters, square yards, or square
centimeters. Whether you're a homeowner planning new
carpet, a contractor pricing concrete, a landscaper estimating a garden bed,
or a renter sizing up an apartment, this free area tool gives you an
accurate answer in seconds — without any spreadsheet math.
This tool supports five shapes: rectangle, multi-room (irregular /
L-shaped layout), circle, triangle, and trapezoid. Each input accepts
feet, inches, yards, meters, or centimeters, so you can measure with
whichever tape you have on hand. Add a price per square foot and the
calculator estimates your material cost — with an optional waste percentage
for cuts, mistakes, and pattern matching.
Square footage calculator diagram: a 12 ft × 10 ft rectangular room equals 120 square feet of total area.
How to Use the Square Footage Calculator
The tool above is built around the most common real-world measurements
for floor area, wall area, and outdoor projects. Pick a tab that matches
the shape of your space and follow these steps:
For a single rectangular room
Measure the length and width of the floor
with a tape measure.
Type both numbers into the calculator and choose your unit of
measurement — feet, inches, yards, meters, or centimeters.
(Optional) Add the ceiling height if you want the
total wall area for painting.
(Optional) Enter a price per square foot and pick a waste percentage.
Click Calculate square footage to see the total area in ft²,
m², and yd², plus your estimated material cost.
For multiple rooms or an L-shaped room
Use the Multi-room tab. Break the floor plan into separate
rectangles, enter the length and width of each one, and the calculator adds
them together. This is exactly how a contractor would quantify the total
square footage of an irregular layout or a whole apartment.
For circles, triangles, and trapezoids
Switch to the matching shape tab and enter the required dimensions. The
calculator handles the geometry for you — useful for round patios, pie-slice
garden beds, gable roof sections, or a trapezoid driveway.
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Square Footage Calculator Formulas (Every Shape)
The math behind an area tool is straightforward once you
know which formula matches your shape. Here are all five, with the
measurement units that go into each calculation:
Rectangle and square footage formula
Square Footage = Length (ft) × Width (ft)
This is the most common calculation in any area measurement. A room 15 ft
long and 12 ft wide is 15 × 12 = 180 sq ft. The same formula works for any
rectangle — a wall, a flat roof section, a driveway, or a warehouse bay.
Circle square footage formula
Round Area = π × (Diameter ÷ 2)² (π ≈ 3.14159)
For a circular patio with a 14 ft diameter, the radius is 7 ft and the
area is 3.14159 × 7² = 153.94 sq ft.
Triangle square footage formula
Triangle Area = (Base × Height) ÷ 2
Use the base (the bottom edge) and the perpendicular height (not the
slanted side). A triangle with a 12 ft base and 8 ft height is (12 × 8) ÷ 2
= 48 sq ft.
Trapezoid square footage formula
Trapezoid Area = ((Base 1 + Base 2) ÷ 2) × Height
A trapezoid has two parallel sides of different lengths. If those bases
measure 10 ft and 14 ft and the perpendicular height is 8 ft, the area is
((10 + 14) ÷ 2) × 8 = 96 sq ft.
Worked Examples with the Square Footage Calculator
Example 1 — Bedroom flooring. A bedroom measures
13 ft × 11 ft. Square footage = 13 × 11 = 143 sq ft. At $4.50 per
square foot for engineered hardwood, the material cost is 143 × $4.50 =
$643.50. With a 10% waste allowance, plan for $707.85.
Example 2 — 30×50 metal building or shop. A
rectangular slab 30 ft × 50 ft is 1,500 sq ft. At $6 per square foot for a
4-inch concrete slab, the estimated cost of materials and labor is $9,000.
Example 3 — L-shaped living room. Split the room
into two rectangles: 14 ft × 10 ft (140 sq ft) and 8 ft × 6 ft (48 sq ft).
Total square footage = 188 sq ft. Use the Multi-room tab to
quantify any irregular layout the same way.
Example 4 — Apartment from inches. A studio
measures 168 in × 144 in. Convert to feet by dividing by 12: 14 ft × 12 ft =
168 sq ft. Or simply choose "Inches" in the calculator and it does
the conversion for you.
Square Footage from Inches, Yards, and Meters
If you measured your room in something other than feet, you have two
options: convert each dimension to feet first and then multiply, or select
the correct unit in the calculator and let it convert for you.
Inches: divide each measurement by 12 to convert to
feet. A wall 144 inches long is 144 ÷ 12 = 12 ft. The product of two
measurements in inches divided by 144 also gives square feet directly.
Yards: multiply by 3 to convert to feet, since 1 yard
= 3 feet. One square yard equals 9 square feet.
Meters: multiply by 3.28084 to convert to feet.
One square meter equals 10.7639 square feet.
Centimeters: divide by 30.48 to convert to feet.
Useful for measurements taken with a metric tape.
For background on the unit itself, see Wikipedia's article on
the square foot
and the National Institute of Standards and Technology's
SI unit reference.
Square Footage Conversions Table
From
To
Multiply by
1 square yard
square feet
9
1 square meter
square feet
10.7639
1 square foot
square inches
144
1 square foot
square meters
0.092903
1 square foot
square centimeters
929.03
1 acre
square feet
43,560
1 hectare
square feet
107,639
How to Estimate Flooring, Tile, Carpet, and Paint Costs
Once the square footage calculator gives you a total area, multiply by
the price per square foot to estimate your project cost. The tool can do
this automatically — just type a price into the optional field. A few rules
of thumb for accurate material needs:
Always add 5–10% waste for straight cuts, and 10–15%
for diagonal patterns or tile borders. The calculator includes a
waste-percentage dropdown so you can pick the right buffer.
Tile and carpet are usually sold per square foot, but
some carpet is still priced per square yard — remember that 1 sq yd =
9 sq ft when comparing quotes.
Hardwood and laminate planks are priced per square
foot per box. Round up to the next full box.
Concrete is sold by the cubic yard. If you have a
slab, calculate square footage first, then multiply by thickness in
feet (4 inches = 0.333 ft) to get cubic feet, and divide by 27 to get
cubic yards. For a full breakdown, use our companion
concrete calculator.
Paint is estimated from wall area, not floor area.
Multiply each wall's length by its ceiling height, add them up, and
plan on roughly 350 sq ft of coverage per gallon for one coat.
Common Uses for a Square Footage Tool
A square footage calculator saves time across dozens of everyday
projects. Some of the most common use cases:
Home improvement: flooring, tile, carpet, hardwood,
laminate, vinyl, baseboards, and paint.
Real estate: measuring a property, apartment, condo,
or rental unit for listings and pricing per square foot.
Construction and contractors: pricing concrete slabs,
roofing, drywall, and insulation.
Landscaping and gardening: sod, mulch, paver patios,
and garden bed area measurements.
Painting and installation: wall area, trim length,
and wallpaper coverage.
Property tax and HOA: verifying recorded square
footage of a house, condo, or lot.
Tips for Accurate Square Footage Measurement
Measure twice. A small error in one dimension is
multiplied across the entire area calculation.
Use the longest tape you can. Joining multiple short
measurements introduces error at every break.
Round to the nearest inch. Avoid eyeballing fractions
— the calculator handles decimals precisely.
For irregular rooms, sketch the floor plan on paper
and divide it into rectangles before you start measuring. That's the
fastest way to quantify total square footage of an L-shape.
For round areas, measure across the widest point to
get the true diameter.
Subtract built-ins. For accurate flooring quotes,
subtract the footprint of permanent islands, fireplaces, or fixed
cabinetry that you won't be flooring under.
For deeper background on area measurement in general, see Wikipedia's
overview of area.
Square Footage Calculator FAQs
How do you calculate square feet of a room?
Measure the length and width of the room in feet, then
multiply them together. A room 12 ft by 10 ft is 120 square feet. For an
L-shaped room, split it into two rectangles, calculate each, and add the
two areas together.
How do I calculate room square footage from inches?
Divide each measurement in inches by 12 to convert to
feet, then multiply length by width. For example, 144 in × 120 in
becomes 12 ft × 10 ft = 120 sq ft. Or simply select "Inches" in the
square footage calculator above and it converts automatically.
How do I calculate square footage of an L-shaped or irregular room?
Split the room into two or more rectangles, calculate
the square footage of each one, and add them together. The
Multi-room tab in the calculator does this for you — just enter
the length and width of each rectangle.
How many square feet is a 10×10 room?
A 10 ft by 10 ft room is 100 square feet (10 × 10 =
100). A 12×12 room is 144 sq ft, a 15×15 is 225 sq ft, and a 30×50 slab
or building is 1,500 sq ft.
How do I calculate square footage for flooring or tile?
Calculate the total floor area in square feet, then add
5–10% for cuts and waste (use 10–15% for diagonal or patterned tile).
Multiply the total by the price per square foot to estimate your
material cost. The tool does this automatically when you enter a
price and a waste percentage.
How is square footage of a circle calculated?
The formula is π × radius². The radius is half the
diameter, so for a 14 ft round patio the radius is 7 ft and the area is
3.14159 × 7² = 153.94 sq ft. Use the Circle tab in the
calculator for an instant result.
How do I convert square meters to square feet?
Multiply square meters by 10.7639. A 50 m² apartment is
50 × 10.7639 = 538.2 sq ft. The calculator also accepts meters and
centimeters directly.
Is this square footage calculator free to use?
Yes. The square footage calculator on Anchor AI Tools
is completely free, requires no signup, and works on any device. All
calculations run in your browser, so your measurements stay private.
Last updated: May 2026 · Estimates from this area tool
are for planning purposes only. Always confirm measurements and material
quantities with a qualified contractor or supplier before purchasing.
