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Area Calculator

Whether you are buying flooring, painting a room, laying sod, or quoting a concrete pour, everything starts with one number: area. This calculator handles six common shapes and reports the result in square feet, square meters, square yards, and acres, so you can move straight to ordering materials with the right units.

Shape & Dimensions

Area Formulas by Shape

ShapeFormulaExample
Rectanglelength × width12 × 14 = 168 ft²
Squareside²10 × 10 = 100 ft²
Circleπ × r²3.1416 × 100 = 314 ft²
Triangle½ × base × height½ × 20 × 10 = 100 ft²
Trapezoid½ × (a + b) × height½ × (10+14) × 6 = 72 ft²
Parallelogrambase × height12 × 8 = 96 ft²

What You Can Cover With That Area

JobAreaMaterial NeededBuying Tip

Material estimates are typical US values and vary by product, coat, and application. For exact quantities use the linked paint, tile-flooring, carpet, and cubic-yards calculators.

How to Use This Calculator (3 Steps)

1
Pick the shape that matches your space
Most rooms are rectangles. Circles suit patios and garden beds; triangles and trapezoids appear in oddly shaped lots and attic floors. For irregular rooms, split into rectangles and add the results.
2
Measure in the unit you already have
Enter feet, inches, yards, or meters — the calculator converts everything to the four common output units automatically, so you never fumble with conversion math mid-project.
3
Use the right number when ordering
Flooring and carpet are sold by square foot or yard; sod by the square foot or pallet; paint by the gallon; and gravel or mulch by the cubic yard. Grab the matching output and add the waste allowance your material needs.

Case Study

📐
Case Study #1

A Landscaper Paves a Curved Patio

A homeowner wants a 20-foot-diameter circular paver patio and needs to quote pavers and sand.

Patio Area
314 ft²
In Square Yards
34.9 yd²
Pavers Needed
1,383
Waste
+10%

Frequently Asked Questions

How do I calculate the area of a room?

Measure length and width and multiply. 12 × 14 ft = 168 sq ft. L-shaped rooms: split into two rectangles and add.

How many square feet in a square meter?

10.764. Multiply square meters by 10.764 to get square feet.

How do I convert square feet to acres?

Divide by 43,560. A quarter-acre lot is 10,890 sq ft.

What is the area of a circle?

π × r². A 20-ft-diameter patio (10-ft radius) is about 314 sq ft.

How much paint or flooring do I need?

Paint: 350-400 sq ft per gallon per coat. Flooring: order 10% extra for waste. Use our dedicated calculators for precision.

B
BuildFormulas Construction Team
Building & Material Estimation

The BuildFormulas Construction Team builds area, volume, and material-quantity tools used by contractors, landscapers, and DIY homeowners for accurate project estimates.

Reviewed by BuildFormulas Editorial Review Board, Editorial Review
Last updated: August 2026