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Room Square Footage Calculator

Need accurate room square footage before you order flooring or plan paint? Enter length and width for a rectangle—or two rectangles for a simple L-shape—and get floor area in square feet and square meters.

Rectangular rooms use Area = length × width. L-shaped rooms are two non-overlapping rectangles added together. Enter whole feet or feet-and-inches consistently (for example 12 ft 6 in as 12.5 ft if your fields use decimal feet). This tool does not add waste, closets you forgot to measure, or cutouts—verify on site and follow product labels for how much to buy.

Room shape
Room dimensions

How the formula works

For a rectangle, area equals length multiplied by width. For an L-shaped room, divide the floor into two rectangles that do not overlap, calculate each area, and add them together. This tool converts between square feet and square meters using 1 m² ≈ 10.764 sq ft.

How it works

For a rectangular room, enter length and width in the same unit (feet or meters). Example: 12 ft × 10 ft = 120 sq ft (about 11.15 m²). For an L-shape, divide the floor into two rectangles that do not overlap, measure each, and enter both dimension pairs—the tool sums the areas. Conversions use 1 m² ≈ 10.764 sq ft. If you measure in feet and inches, convert inches to a decimal (6 in = 0.5 ft) before multiplying, or convert both sides to inches and divide by 144 for square feet.

How to calculate room square footage

Floor area for a rectangular room equals length × width. Measure wall to wall at floor level in the same unit (feet or meters). Multiply those two numbers to get square feet or square meters—for example, 12 × 10 = 120 sq ft.

Choose feet or meters in the calculator and keep both dimensions in the same unit. The result shows both square feet and square meters so you can match product labels sold in either system.

Feet and inches: convert to decimal feet (12 ft 6 in → 12.5) or to inches (150 × 120 = 18,000 in² ÷ 144 = 125 sq ft). Mixing feet on one side and inches on the other is a common error.

Wall paint area is different: it uses wall length × ceiling height (minus openings), not floor square footage alone. Use this tool for floor area; use the paint coverage calculator and painting guides for wall estimates.

L-shaped and irregular rooms

For a simple L-shape, split the floor into two rectangles that do not overlap—for example, the main rectangle plus an alcove. Measure each section, enter both in L-shaped mode, and add the areas.

Sketch the room and label each rectangle so you do not double-count the corner where they meet. Closets and bump-outs count if flooring or finish will cover them.

Complex curves, diagonal walls, or many cutouts need a sketch and field judgment beyond this tool. Measure twice before ordering expensive flooring.

Common measuring mistakes

Using floor square footage as wall paint area is a frequent error—paint estimates need wall length multiplied by ceiling height, minus openings.

Measuring inside trim instead of wall-to-wall when flooring runs under baseboard can under-order material.

Forgetting to split L-shaped rooms into non-overlapping rectangles skips closet or alcove area—or double-counts the shared corner if you overlap.

Mixing units (feet vs inches) or rounding every measurement up before multiplying can inflate or shrink the order. Convert cleanly, then add manufacturer waste separately.

Important limitations

Results are mathematical estimates based on the dimensions you enter. They do not account for waste factor, irregular shapes beyond a simple L-shape, or obstacles. This tool does not provide construction, structural, or engineering advice. Always verify measurements on site and follow product manufacturer guidance for material quantities.

What to do next

Take your square footage into the flooring calculator to estimate material with waste, or the paint coverage calculator for wall/ceiling gallons. Read how to measure for flooring for tape technique, underlayment, and waste rules before you buy.

Frequently asked questions

How do I calculate the square footage of a room?
Measure length and width in the same unit, then multiply: Area = length × width. A 12 ft by 10 ft room is 120 square feet. Use this calculator to convert to square meters as well.
How do I measure an L-shaped room?
Divide the room into two rectangles that do not overlap—for example, the main body of the room and an alcove or bump-out. Measure each rectangle separately and enter both in the L-shaped mode so the areas add without double-counting.
How do I enter feet and inches?
Convert to decimal feet (6 inches = 0.5 ft) before entering, or convert both dimensions to inches, multiply, and divide by 144 for square feet. Keep both sides in the same unit.
Should I add extra for waste?
Most flooring and paint projects need extra material for cuts, mistakes, and pattern matching. Product labels often suggest a waste percentage—this calculator gives base area only. Add waste in the flooring calculator or paint coverage calculator next.
What can this number help me estimate?
Square footage is the starting point for flooring orders, paint coverage estimates, and comparing product labels. It does not tell you how much to buy by itself—you still need the product's coverage rate and any waste factor the manufacturer recommends.

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