To convert a mixed measurement such as 5 ft 7 in, use the Feet and inches (optional) field in Length Converter. Keep the feet and inches labeled. Entering 5.7 in the ordinary Value field means 5.7 feet, which is a different length.
Enter feet and inches in the dedicated field
- Open Length Converter and choose Centimeters (cm) under Convert to.
- Enter
5 ft 7 inin Feet and inches (optional). This entry takes precedence over the ordinary Value and Convert from controls, so clear it when you return to a single-unit conversion. - Choose the number of significant digits in displayed results. Six is enough to show this example as
170.18 cm. - The result updates automatically. Check the entered measurement and result together.
The ordinary Value field accepts a number, not a labeled expression. For decimal feet instead, clear the optional feet-and-inches field, enter 5.7 in Value and choose Feet under Convert from.
Check the arithmetic
Five feet contain 60 inches. Adding seven gives 67 inches, and 67 × 2.54 = 170.18 cm. The inch is exactly 2.54 centimeters.
| Input | Meaning | Centimeters before display rounding |
|---|---|---|
5 ft 7 in |
5 feet plus 7 inches | 170.18 |
5.7 with Feet selected |
5 feet plus 8.4 inches | 173.736 |
The decimal point does not separate feet from inches. In 5.7 feet, the fractional 0.7 × 12 contributes 8.4 inches.
For a half inch, use a decimal such as 5 ft 7.5 in. Do not paste 5 ft 7 1/2 in: the mixed-entry field accepts decimal numbers, rather than slash fractions. Spell out ft and in if copied quote marks are unclear.
Round the display without overstating accuracy
The precision control offers 4, 6, 10 or 12 significant digits. These are total meaningful digits, not decimal places. At four significant digits, the example displays as 170.2 cm; at six, it displays as 170.18 cm.
More displayed digits do not make the original measurement more accurate. If it was recorded to the nearest inch, keep that uncertainty in mind when using the centimeter result. Leave the original labeled measurement beside the conversion.
Convert each dimension separately
To check whether an object fits, compare height, width and depth independently with the available space. Converting the largest dimension does not establish that the other two fit.
For a diagram or model, Scale Drawing Calculator applies a drawing-to-real ratio after the units are explicit. A length conversion alone does not apply a drawing scale.
For a floor area, use Area Converter. The square-foot conversion uses the length factor squared. An area's units and a perimeter's units describe different quantities.