Feet and Inches Calculator

Add or subtract measurements in feet, inches and fractional inches. Use the result as a room dimension when you are ready to calculate its area.

First measurement
Second measurement

Enter whole feet and decimal or fractional inches, such as 6.5 or 6 1/2.

Result

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Measurements are calculated before display rounding. Results are shown to four decimal places where needed.

Choose which dimension this result represents. Enter the other dimension in the room area calculator.

How to add feet and inches

Convert each measurement to inches: feet × 12 + inches. Add or subtract, then divide by 12 to find whole feet and the remaining inches.

12 ft 6½ in + 3 ft 8 in = 16 ft 2½ in

Fractional inches are not decimal feet

6 1/2 inches means 6.5 inches. 12 feet 6 inches equals 12.5 feet, not 12.6 feet. Inches above 12 are carried into feet automatically.

1 ft = 12 in = 0.3048 m

From a length to a room area

One length cannot determine a room’s area. Measure the perpendicular side too, then multiply the two dimensions. Keep door positions and furniture sizes for layout planning.

Room Area Calculator →