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Square Footage Calculator – Calculate Square Feet for Rooms, Flooring & More

Use the free Square Footage Calculator – Calculate Square Feet for Rooms, Flooring & More on Find New Daily for quick, clear estimates. Enter your measure…

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Room Square Footage Calculator

Calculate square footage of a room or area by selecting a shape and entering measurements.

Shape

Measurement Unit

Quantity

Measuring a room for the Square Footage Calculator – Calculate Square Feet for Rooms, Flooring & More

Measure once, calculate clearly

A simple way to measure a room

Start with the longest wall and measure from finished surface to finished surface. Write down feet and inches separately, then repeat for the width. Small alcoves and closets are easier to handle as separate rectangles; calculate each piece and add the totals.

For a basic rectangular room, multiply length by width. A 12 ft by 10 ft room is 120 sq ft. The calculator above also handles circles, triangles, trapezoids, several rooms, flooring waste, paint, roofing, landscaping, and price per square foot.

Plan materials before checkout

Why the final purchase can be larger than the room

Flooring, tile, turf, and roofing rarely use every piece perfectly. Cuts at walls, damaged boards, pattern matching, and awkward corners create waste. A straightforward room may need about 5% extra, while diagonal patterns or irregular spaces can need 10% to 15% or more.

Keep the base measurement and the waste allowance separate. That makes the estimate easier to review and gives you a useful record when comparing box coverage, contractor quotes, or cost per square foot.

Planning flooring materials with the Square Footage Calculator – Calculate Square Feet for Rooms, Flooring & More

Read the complete square footage guide

Square footage formulas

Break an irregular space into familiar shapes. Calculate each shape on its own, then add the results. This is usually more reliable than trying to force the whole outline into one formula.

Shape	Formula
Rectangle	Length × Width
Square	Side × Side
Triangle	Base × Height ÷ 2
Circle	π × Radius²
Trapezoid	(Base 1 + Base 2) × Height ÷ 2

Feet, inches, and unit conversions

Convert inches to a fraction of a foot before multiplying. Divide inches by 12: 6 inches is 0.5 ft, 3 inches is 0.25 ft, and 9 inches is 0.75 ft. The calculator does this conversion for you when feet and inches are entered in separate fields.

From	Conversion
Square feet to square yards	Divide by 9
Square feet to square meters	Divide by 10.7639
Square feet to acres	Divide by 43,560
Roof area to roofing squares	Divide by 100

Room-size examples

Room dimensions	Area
8 × 10 ft	80 sq ft
10 × 10 ft	100 sq ft
10 × 12 ft	120 sq ft
12 × 12 ft	144 sq ft
12 × 15 ft	180 sq ft
15 × 20 ft	300 sq ft
20 × 20 ft	400 sq ft

Practical notes for common projects

Flooring and tile

Check the coverage printed on each box and round the box count up. Keep unopened spare material when possible because the same style or dye lot may be difficult to match later.

Paint

Wall texture, primer, color changes, and the number of coats affect coverage. Use the manufacturer’s label as the final guide rather than treating a general coverage figure as a guarantee.

Roofing

Pitch, overhangs, valleys, hips, dormers, and skylights can make the real roof surface larger than the building footprint. Use the result for early planning and confirm a final order with a qualified roofer.

Real estate

Finished living area, basements, garages, porches, and unfinished rooms may be reported differently depending on local practice. For a listing, appraisal, or legal document, follow the measurement standard used in your area.