Online Square Footage 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 Unit ($)

Calculate border only (perimeter)

Rectangle

Area

0.00

Perimeter

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.

Online Square Footage Calculator — Free, Fast & Accurate

Our online square footage 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 area 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 Estimation

Enter a cost per square unit 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 Online Area 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 unit to estimate materials cost.
5. Check "Calculate border only" if you only need the perimeter.
6. Click "Calculate" to see the area and perimeter results, 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 Online?

Knowing the square footage of a space is essential for flooring, painting, landscaping, and construction projects. Our free square footage calculator saves you time and reduces errors compared to manual calculations. It's perfect for homeowners, contractors, real estate agents, and DIY enthusiasts.

Frequently Asked Questions

Can I calculate the area of an irregular shape?

This tool focuses on regular shapes. For irregular shapes, you can break them into smaller regular shapes, calculate each, and sum the areas.

What does "Calculate border only" mean?

When checked, the tool will only compute the perimeter (or circumference for circles) of the shape, which is useful for projects like fencing, baseboards, or crown molding.

Is this calculator accurate?

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

Do I need an internet connection?

Once the page loads, the calculator works offline. All calculations are performed locally in your browser.

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

View Detailed Tutorial →