Square Foot Calculator

Calculate area and perimeter for rectangles, circles, triangles, trapezoids, parallelograms, and ellipses. Supports ft, in, yd, m, cm, mm.

Shape

Unit

Cost per Square Foot ($)

Calculate border only (perimeter)

Rectangle

Area

0.00

Perimeter

0.00

Total Cost

$0.00

Dimensions

Select a shape and enter dimensions

🔒💻

Privacy First — No Server Uploads
All calculations happen locally in your browser. No data is sent to any server. No signup, no tracking, no storage.

Square Foot Calculator — Free, Fast & Accurate

Our square foot calculator helps you quickly determine the area of any room, property, or space. Whether you're planning a home renovation, installing new flooring, painting walls, or working on a construction project, this square footage calculator gives you instant results in square feet, square meters, and square inches. Enter your measurements in feet and inches or meters — the choice is yours.

📐 6 Shapes

Rectangle, circle, triangle, trapezoid, parallelogram, and ellipse — all in one tool.

📏 Multiple Units

Feet, inches, yards, meters, centimeters, millimeters — switch instantly.

💰 Cost Estimator

Enter a cost per square foot to instantly see your total project cost.

🔄 Perimeter Option

Check "Calculate border only" to focus on perimeter — great for fencing, baseboards, and trim.

🎨 Visual Shape Display

See the shape with dimension labels directly on the graphic.

🔒 100% Private

All calculations are local. No data leaves your device.

How to Use This Square Foot Calculator

1. Select the shape you want to measure.
2. Choose your preferred unit (ft, in, yd, m, cm, mm).
3. Enter the required dimensions — the input fields change based on the shape.
4. Optionally, enter a cost per square foot to estimate material costs.
5. Check "Calculate border only" if you only need the perimeter.
6. Click "Calculate" to see the area, perimeter, and total cost, with the shape displayed on the right.

Square Footage Formulas

Rectangle: Area = length × width, Perimeter = 2(length + width)
Circle: Area = π × radius², Circumference = 2π × radius
Triangle: Area = ½ × base × height, Perimeter = side1 + side2 + side3
Trapezoid: Area = ½ × (base1 + base2) × height, Perimeter = base1 + base2 + side1 + side2
Parallelogram: Area = base × height, Perimeter = 2(base + side)
Ellipse: Area = π × semi-major × semi-minor, Perimeter (approx.) = 2π × sqrt((a²+b²)/2)

Why Calculate Square Footage?

Flooring Projects — Determine how much carpet, tile, or hardwood you need.
Painting & Wallpaper — Estimate wall area for paint or wallpaper coverage.
Real Estate — Measure property square footage for listings or appraisals.
Landscaping — Calculate lawn size, garden beds, or patio areas.
Construction — Plan material quantities and project budgets.

Frequently Asked Questions

What is a square foot?

A square foot is a unit of area measurement equal to a square measuring one foot on each side. It's the most common unit for measuring floor space, room size, and property area in the United States.

How do I calculate square footage?

Multiply the length by the width. For example, a room that is 12 feet long and 10 feet wide has 120 square feet of area (12 × 10 = 120). Our square foot calculator does this instantly for any shape.

What's the difference between square feet and square meters?

One square meter equals approximately 10.764 square feet. Our calculator shows results in both units so you can easily compare.

Can I use this for irregular shapes?

This tool handles 6 common shapes. For irregular shapes, break them into smaller regular shapes, calculate each, and add the areas together.

Is this square foot calculator accurate?

Yes. It uses standard mathematical formulas with up to 4 decimal places of precision. Results are reliable for construction, design, and real estate purposes.

Learn how to use this tool correctly by reading our step-by-step tutorial.

View Detailed Tutorial →