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Convert Inches to Centimeters – Length Converter

This converter converts values expressed in inches into centimeters using the internationally agreed conversion factor. It also explains how to handle common composite inputs given as feet and inches (for example, 5 ft 7 in).

The mathematical relationship used here is exact: 1 inch = 2.54 centimeters. While the arithmetic conversion is exact, any physical measurement you perform may include instrument error and should be interpreted with appropriate rounding and traceability to calibration standards.

Updated Nov 21, 2025

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Methodology

The tool multiplies the numeric inch value by the defined conversion factor 2.54 to compute centimeters. For combined feet+inches input, convert feet to inches first (feet × 12), add the leftover inches, then apply the same factor.

Results are calculated using standard floating-point arithmetic for speed and ease of use. For reporting or technical work, follow local or industry rules for significant figures and document measurement uncertainty and calibration traceability (for example, ISO/IEC 17025 and NIST-traceable calibration).

Worked examples

Convert 5 ft 7 in to cm: total_inches = (5 × 12) + 7 = 67 in; centimeters = 67 × 2.54 = 170.18 cm.

Convert 70 in to cm: centimeters = 70 × 2.54 = 177.8 cm.

Further resources

Expert Q&A

Can I enter feet and inches directly?

This converter accepts a single numeric input in inches. To convert feet+inches, first convert feet to inches (feet × 12), add the remaining inches, then input the total inches here or use the built-in guidance to compute the total before conversion.

Is 1 inch exactly 2.54 cm?

Yes. The inch is defined as exactly 25.4 millimetres which makes 1 inch = 2.54 cm exact by international agreement. The exact mathematical factor is used in the computation.

How should I round the result?

Round based on the precision of your original measurement and the needs of your task. For simple everyday use two decimal places is common. For scientific or regulated work, follow your discipline's significant-figure rules and report measurement uncertainty.

What about measurement accuracy and calibration?

The arithmetic conversion is exact, but physical measurements have uncertainty. For traceable, calibrated measurements use instruments calibrated to standards recognized under ISO/IEC 17025 and traceable to NIST or equivalent national metrology institutes. Document calibration certificates and measurement uncertainty when required.

Can I convert centimeters back to feet and inches?

Yes. Convert centimeters to inches by dividing by 2.54, then separate into feet and remaining inches: feet = floor(total_inches / 12); inches = total_inches − (feet × 12). For integer-inch results you may round the remainder as appropriate.

Sources & citations