Precision Measurement Tool
Best Free Square Foot Calculator
The most elegant way to measure any space. From simple rooms to complex shapes — get pixel-perfect area calculations with our interactive visual tool.
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Multi-Shape Calculator
Calculate Any Shape Instantly
Choose a shape below and enter your measurements. Get instant, accurate area calculations.
Rectangle / Square
Enter the width and length of the rectangular area.
Total Area
0 Square Feet
Circle
Enter the radius or diameter of the circular area.
Total Area
0 Square Feet
Triangle
Enter the base and height of the triangle.
Total Area
0 Square Feet
L-Shaped Room
Treat the L-shape as two rectangles. Enter dimensions for each section.
Section 1
Section 2
Total Area
0 Square Feet
Trapezoid
Enter the two parallel sides (bases) and the height.
Total Area
0 Square Feet
Quick Converter Unit
Unit Conversion
Convert between square feet, square meters, square yards, and acres instantly.
Visual Interactive Diagram
See How It Works
Watch the measurement come alive. Enter dimensions and see the area calculated in real time on the diagram.
Interactive Room Planner
Adjust the width and length below to see the room dimensions update dynamically on the diagram. The shaded area represents the calculated square footage.
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Real-time dimension updates on the diagram 🎨
Visual area fill shows the measured space ⚡
Instant calculation as you type Simple Process
How It Works
Three simple steps to get an accurate area measurement for any space.
1
Choose a Shape
Select the shape that best matches your room or area — rectangle, circle, triangle, L-shape, or trapezoid.
2
Enter Measurements
Input your dimensions in your preferred unit of measurement — feet, inches, meters, centimeters, or yards.
3
Get Instant Results
See your square footage calculated instantly, with visual feedback on the interactive diagram and precise numeric results.
How to Calculate Square Footage
Square footage is the area of a flat surface measured in feet. To calculate square footage, measure the length and width of a space in feet (ft), then multiply length × width to get the area in square feet (sq ft or ft²). Square yardage is area measured in yards, and square meters (sq m) is area measured in meters (m).
This square footage calculator estimates the area of a lot, house, or room in 9 common shapes, including rectangle, circle, triangle, trapezoid, sector, and parallelogram. For complex or irregular-shaped areas, split the space into simpler shapes, calculate each section, and add the areas together.
Basic Formula for Area
Area is the amount of space occupied by a 2-dimensional shape. The shape can be a floor, wall, field, or garden.
The simplest formula for calculating area is for a rectangular or square shape:
Area (ft²) = Length (ft) × Width (ft)
Measure the length and width of a rectangular room in feet. Multiply length × width to get the area in square feet (ft²). Convert measurements to feet first, if the measurements are in different units like inches (in) and feet (ft).
Basic Length Conversion
Convert other units of measure to feet with these 4 formulas:
- Inches to feet: Divide inches by 12 to get feet (e.g., 72 in ÷ 12 = 6 ft)
- Meters to feet: Multiply meters by 3.28084 to get feet (e.g., 3 m × 3.28084 = 9.84 ft)
- Centimeters to feet: Divide centimeters by 30.48 to get feet (e.g., 150 cm ÷ 30.48 = 4.92 ft)
- Yards to feet: Multiply yards by 3 to get feet (e.g., 5 yd × 3 = 15 ft)
Example Calculation
Bedroom Square Footage
A bedroom measures 16 feet (4.88 m) by 12 feet (3.66 m).
16 ft × 12 ft = 192 square feet (17.84 sq m)
192 square feet equals approximately 21.33 square yards (sq yd) or 0.0044 acres.
Area Conversion
Measure your space in any unit — inches, centimeters, feet, meters, or yards — calculate the area, then convert the result to the unit you need. The table below shows 4 standard area conversion factors:
| Unit | Square Feet Equivalent |
|---|---|
| 1 acre | 43,560 square feet (4,046.86 sq m) |
| 1 square yard (sq yd) | 9 square feet (0.836 sq m) |
| 1 square meter (sq m) | 10.764 square feet |
| 1 square inch (sq in) | 0.00694 square feet (6.452 sq cm) |
Area Formulas for Different Shapes
There are 13 common area formulas for calculating square footage of different shapes. Each formula uses measurements in feet to produce results in square feet (ft²).
Square Shape
Calculate square footage of a square
Area (ft²) = Side Length²
Length equals width in a square, so area is side length squared. A square with 10 ft (3.05 m) sides has an area of 100 sq ft (9.29 sq m).
Rectangle Shape
Calculate square footage of a rectangle
Area (ft²) = Length × Width
Multiply the length by the width in feet. A 20 ft × 15 ft (6.1 m × 4.57 m) rectangle has an area of 300 sq ft (27.87 sq m).
Circle Shape
Calculate square footage of a circle
Area (ft²) = π × (Diameter ÷ 2)²
π = 3.14159265359. A circle with a 10 ft (3.05 m) diameter has an area of 78.54 sq ft (7.3 sq m).
Triangle (Base & Height)
Calculate square footage of a triangle
Area (ft²) = ½ × Base × Height
Measure the base and the perpendicular height in feet. A triangle with a 12 ft (3.66 m) base and 8 ft (2.44 m) height has an area of 48 sq ft (4.46 sq m).
Trapezoid Shape
Calculate square footage of a trapezoid
Area (ft²) = [(a + b) ÷ 2] × h
a and b are the 2 parallel sides (bases). h is the perpendicular height. A trapezoid with bases of 14 ft and 10 ft and height of 8 ft has an area of 96 sq ft (8.92 sq m).
Sector
Area (ft²) = (θ ÷ 360) × π × r²
θ is the central angle in degrees. r is the radius. A sector with a 90° angle and 6 ft (1.83 m) radius has an area of 28.27 sq ft (2.63 sq m).
Parallelogram
Area (ft²) = Base × Height
Base is the bottom side length; height is the perpendicular distance between the base and the opposite side. A parallelogram with a 15 ft base and 9 ft height has an area of 135 sq ft (12.54 sq m).
Calculations for 'L' Shaped Rooms or Areas
Split an L-shaped room into 2 separate rectangles. Measure the length and width of each rectangle in feet. Calculate the area of each rectangle, then add both areas together for the total square footage.
- Sketch the floor plan on paper and divide the L-shape into 2 rectangles.
- Measure the length and width of each rectangle in feet (ft).
- Multiply length × width for each rectangle to get 2 separate areas.
- Add both areas together for the total square footage.
L-Shaped Living Room + Dining Area
Section A (living room): 14 ft × 10 ft = 140 sq ft (13.01 sq m)
Section B (dining area): 6 ft × 5 ft = 30 sq ft (2.79 sq m)
140 sq ft + 30 sq ft = 170 square feet (15.79 sq m)
Calculating Square Footage for Walls
To calculate the square footage of a wall for painting or decorating, follow these 4 steps:
- Measure the height of the wall from floor to ceiling in feet (do not include baseboards and moldings).
- Measure the full length of the wall in feet, including doors and windows.
- Multiply height × length to get the total wall area in square feet.
- Subtract the area of windows, doors, and closets that will not be painted or covered.
Add 10% extra material to the final square footage total for waste and coverage variations.
Calculating the Square Footage of a House
To calculate the total square footage of a house, measure the width and length of the entire exterior in feet. Multiply width × length for each floor. Add the area of each floor together for the total home square footage.
To calculate only the living space square footage, measure each room separately with these 4 steps:
- Create a floor plan: Sketch a floor plan of each level of the house.
- Measure individual rooms: Measure the length and width of each room from wall to wall in feet (ft) or meters (m).
- Multiply length × width: Calculate the area of each room in square feet and write each area on the plan.
- Add all room areas: Add the square footage of all rooms together for the total living space.
Include: Hallways, staircases, closets, and foyers in the living space total.
Exclude: Garages, unfinished basements, and utility rooms — these are not part of the living space.
Calculate Cost of Materials
To estimate material cost for a construction project, first calculate total area, then multiply by your local price per unit area.
- Use: Total Cost = Total Area x Price per unit area. For tile sold in boxes, divide box price by box coverage to get price per square foot.
- Select the unit of area (square feet, square inch, square yard, or square meter).
Calculating Cost Per Square Foot
Square footage pricing determines the cost of painting a house, flooring installation, and building a home. The square footage of a property sets the baseline for cost estimates and material quantities.
Painting a House
Professional house painters base price quotations on the square footage of a property. Measuring square footage produces accurate estimates of the amount of paint needed for a paint job.
Total painting cost includes 5 cost factors: paint, brushes, turpentine, paint primer, and labor. Paint primer helps paint adhere to surfaces like wood, metal, and plastic. Primer covers 200–400 square feet (18.58–37.16 sq m) per gallon (3.79 liters), and paint covers 350–400 square feet (32.52–37.16 sq m) per gallon on average.
Flooring Installation
There are 3 main categories of flooring materials: wood, laminate, and tile. Flooring costs vary based on the quality and type of material chosen.
Wood Flooring — Hardwood is durable, easy to clean, and available in many appearances. Engineered wood has higher heat and moisture resistance than solid hardwood and costs less. Bamboo flooring is moisture resistant and available in many styles at a lower price point.
Laminate Flooring — Made from fiberboard with a plastic laminate top layer. Costs less than wood, resists scratches and dents, and requires little maintenance. Installs over existing flooring.
Tile Flooring — Includes concrete, cement, ceramic, glass, and natural stone. Prices range from $0.60 to over $100 per square foot. Easy to maintain, suitable for all locations.
Building a Home
Building cost per square foot varies based on materials, foundation type, roof pitch, and many other factors. Cost per square foot for building a home is estimated based on regional averages.
Adding 10% Surplus for Materials
Order 10% more material than the calculated square footage to account for waste from cutting, fitting, and installation errors.
Waste Percentages by Material Type
Vinyl / Laminate (simple layouts)5–10% extra
Vinyl / Laminate (complex rooms)10–15% extra
Carpet10% extra
Ceramic Tiles10–15% extra
Hardwood Flooring10% extra
Paint10% extra
Example with 10% Waste Factor
Calculated area: 170 sq ft (15.79 sq m)
170 sq ft × 1.1 = 187 square feet (17.37 sq m) of material to order
Common Questions
Frequently Asked Questions
Measure length and width for squares or rectangles, and use shape-specific formulas for circles, triangles, and trapezoids. For a rectangle, multiply length × width. For a circle, use π × (diameter ÷ 2)². For a triangle, use ½ × base × height. This square footage calculator supports 9 shapes and returns results in square feet, square meters, square yards, and acres.
Measure the length and width of the room in feet, then multiply length × width. A room measuring 12 ft (3.66 m) wide and 16 ft (4.88 m) long has an area of 192 square feet (17.84 sq m). For an L-shaped room, split the space into 2 rectangles, calculate each area, and add them together.
Calculate the area in square inches (length × width in inches), then divide by 144 to convert to square feet. 1 square foot equals 144 square inches. For example, 1,728 sq in ÷ 144 = 12 sq ft (1.11 sq m). This calculator handles the conversion automatically when "Inches" is selected as the unit.
Yes, this calculator converts square feet to square yards, square inches, square meters, and acres. 1 sq ft = 0.0929 sq m. 1 sq ft = 0.1111 sq yd. 1 acre = 43,560 sq ft. Use the unit conversion section to switch between 5 area units instantly.
A 10×10 room is 100 square feet (9.29 sq m or 11.11 sq yd). Multiply 10 ft × 10 ft = 100 sq ft. This equals approximately 0.0023 acres.
Split the irregular shape into simpler shapes like rectangles, triangles, or circles. Calculate the area of each section separately, then add all areas together. Sketch a floor plan on paper to identify the simplest way to divide the space. The L-shaped room calculator handles the most common irregular layout.
Measure each room's length and width in feet, multiply to get the area, and add 10% extra for waste. For a 170 sq ft room: 170 × 1.1 = 187 sq ft of flooring material to order. Waste rates vary by material: vinyl/laminate needs 5–15% extra, carpet needs 10% extra, ceramic tiles need 10–15% extra, and hardwood needs 10% extra.
Multiply square feet by 0.0929 to get square meters. For example, 200 sq ft × 0.0929 = 18.58 sq m. To convert square meters to square feet, multiply by 10.764. The unit converter above performs this conversion instantly for any value.
Yes, this calculator estimates area and material needs for gardens, walkways, patios, and other outdoor spaces. Select the shape that matches the outdoor area, then enter dimensions in feet or meters to calculate total area. To estimate cost, multiply the area by your local price per square foot.
The area of a circle equals π × radius². A circle with a 5 ft (1.52 m) radius has an area of 78.54 sq ft (7.3 sq m). A circle with a 10 ft (3.05 m) diameter (5 ft radius) produces the same 78.54 sq ft result. Use π = 3.14159265359 for precise area estimation.
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Reference
| Conversion | Value |
|---|---|
| 1 acre | 43,560 square feet (4,046.86 sq m) |
| 1 square yard | 9 square feet (0.8361 sq m) |
| 1 square meter | 10.764 square feet |
| 1 square inch | 0.00694 square feet (6.452 sq cm) |
| 1 square foot | 144 square inches (929.03 sq cm) |
Summary of Calculations
| Space Type | Calculation (in feet) |
|---|---|
| Rectangular room/area | Width ? Length |
| L-shaped room/area | Split into rectangles, calculate each, add together |
| Wall | Height ? Length (subtract windows, doors, closets) |
| House | Sketch floor plan, measure each room separately |
| Triangular area | ? ? Base ? Height |
| Circular area | ? ? (Diameter ? 2)? |
| Trapezoid area | [(a + b) ? 2] ? h |
| Sector area | (? ? 360) ? ? ? r? |
| Parallelogram area | Base ? Height |