Square Footage Calculator
Use this square footage calculator to measure rooms, walls, floors, yards, and other spaces from feet, inches, meters, or mixed dimensions with clear area totals.
Square Footage Calculator
Measure one space or many. Add a section for each room, wall, or patio, and mark doors, windows, and cutouts as subtractions — the total comes out net.
Identical copies of this section.
Waste, packages and cost — optional
Applied after cutouts.
From the product label.
In your own currency.
Enter values above to see results
Measurement note: Results depend on the dimensions entered. Measure carefully and verify material coverage, waste allowances, and project specifications before buying supplies.
About This Square Footage Calculator
This tool finds the area of one or more spaces and converts the result into common area units. Choose a shape, enter its dimensions, and add extra sections when a room, wall, floor, garden, or lot cannot be represented by one rectangle.
Optional settings subtract openings, add material waste, count packages, and estimate cost. Users who only need area can leave these fields blank.
How to Use the Square Footage Calculator
- Select the shape that matches the space.
- Enter the required dimensions.
- Choose the unit used for that section's measurements.
- Add a quantity for identical areas.
- Add another section for different dimensions.
- Mark doors, windows, columns, or cutouts as subtractions.
- Enter an optional waste percentage, coverage per package, or price per square foot.
- Click Calculate and review the total.
Labels such as Bedroom, Wall 1, Patio, or Garden make multi-area results easier to check, and they appear in the section breakdown under the result.
What Is Square Footage?
Square footage measures area in square feet. One square foot is the area of a square measuring one foot by one foot.
Area is different from length. A room that is 12 feet long and 10 feet wide covers 120 square feet because the two dimensions are multiplied.
How to Calculate Square Footage
For a rectangle:
Area = Length × Width
Example:
Length: 14 feet
Width: 11 feet
Calculation: 14 × 11
Area: 154 square feet
A square footage calculator is useful when measurements include feet and inches, several rooms must be combined, or parts of a surface need to be added or subtracted.
Formulas for Common Shapes
| Shape | Area Formula |
|---|---|
| Rectangle | Length × Width |
| Square | Side² |
| Triangle | ½ × Base × Height |
| Circle | π × Radius² |
| Trapezoid | ½ × (Base 1 + Base 2) × Height |
| Parallelogram | Base × Perpendicular Height |
| Circular sector | Angle ÷ 360 × π × Radius² |
For triangles, trapezoids, and parallelograms, use the perpendicular height rather than a sloped side.
Calculating With Feet and Inches
Convert inches into part of a foot before multiplying:
Decimal Feet = Feet + Inches ÷ 12
For a space measuring 10 feet 6 inches by 8 feet 3 inches:
10 feet 6 inches = 10.5 feet
8 feet 3 inches = 8.25 feet
Area = 10.5 × 8.25
Area = 86.625 square feet
Choosing Feet & inches as the section's unit gives each dimension its own feet box and inches box, which makes this conversion automatic. Either box may be left blank when a measurement is a whole number of feet or inches.
Adding Multiple or Irregular Areas
Calculate each section separately, then add the results:
Total Area = Area 1 + Area 2 + Area 3
For an L-shaped room, divide the layout into smaller rectangles or other supported shapes. Add included sections and subtract cutouts.
| Section | Area |
|---|---|
| Main room | 224 ft² |
| Hallway | 48 ft² |
| Closet | 18 ft² |
| Total | 290 ft² |
Use quantity for identical sections and separate entries when dimensions vary.
Subtracting Doors and Windows
For a wall or surface with openings:
Net Area = Full Surface Area − Total Opening Area
A 15-foot-by-9-foot wall covers 135 square feet. Subtracting a 21-square-foot door and a 12-square-foot window gives 102 square feet.
Whether openings should be removed depends on the material and installation instructions.
Material Waste and Estimated Cost
Cuts, pattern matching, damage, layout direction, and packaging can increase the amount required.
Required Area = Net Area × (1 + Waste Percentage ÷ 100)
A measured area of 500 square feet with 10% overage becomes 550 square feet.
Estimated Cost = Required Area × Price per Square Foot
For packaged material:
Packages Required = Required Area ÷ Coverage per Package
Package quantities are rounded up, because part of a box cannot be bought. The waste allowance is applied to the net area, after the cutouts have come out — applying it first pads an area that is about to shrink. The estimate does not include labor, delivery, taxes, trim, adhesives, or equipment.
Square Feet and Other Area Units
| Area Unit | Equivalent |
|---|---|
| 1 square foot | 144 square inches |
| 1 square foot | 1/9 square yard |
| 1 square foot | 0.09290304 square meters |
| 1 square yard | 9 square feet |
| 1 acre | 43,560 square feet |
Convert the final area instead of repeatedly rounding each section.
Linear Feet vs Square Feet
Linear feet measure length in one direction. Square feet measure a two-dimensional surface.
A wall may be 20 linear feet long. If it is 8 feet high, its surface area is 160 square feet. Trim is often measured by length, while flooring and wall coverings are measured by area.
Common Measurement Mistakes
Avoid:
- Mixing units without converting them
- Using a sloped side as the height
- Forgetting closets, alcoves, or landings
- Subtracting openings that should remain included
- Applying waste before subtracting cutouts
- Rounding every section too early
- Failing to round package quantities up
Measure twice where practical and use consistent precision.
Start Measuring
Enter the dimensions above and use the square footage calculator to find the net area, combine multiple sections, and review optional material and cost estimates.
Frequently Asked Questions
What does a square footage calculator do?
It calculates area from the entered dimensions and can combine sections, convert units, subtract openings, and estimate material or cost totals.
Can the tool use feet and inches?
Yes. Choose Feet & inches as the unit for a section and each dimension gets its own feet box and inches box. The values are converted before the area is calculated, so 10 ft 6 in by 8 ft 3 in comes out as 86.63 square feet rather than anything you have to work out yourself.
How do I measure an L-shaped room?
Divide it into rectangles or other simple shapes, add each one as its own section, and the calculator adds them together. The section breakdown lists each piece so the total can be checked.
Can I calculate several rooms together?
Yes. Add each room as a separate section and review the combined net total. Labels such as Bedroom, Wall 1, or Patio make a multi-area result much easier to check afterwards.
How do I calculate a circular area?
Measure the radius from the center to the edge, square it, and multiply by π. Choose the Circle shape and enter the radius; for part of a circle, use the Circular sector shape and add the angle.
How much extra material should I add?
The allowance depends on the material, pattern, layout, installation method, and packaging. Around 10% is common for a straight layout, rising for diagonal or patterned work. Check the product instructions or ask the installer.
Should waste be added before or after subtracting cutouts?
After. The waste allowance applies to the net area, once doors, windows, and other cutouts have come out. Adding it first pads an area that is about to shrink and over-orders material.
Why might a contractor's estimate differ?
Measurements, excluded areas, waste, rounding, product coverage, and installation assumptions may differ. The estimate here also excludes labor, delivery, taxes, trim, adhesives, and equipment.