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, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 3517711e2d37 • Reviewed by Fidamen Standards Committee

Interactive converter unavailable for this calculator.

We could not resolve compatible units for this experience. Please verify the slug follows the pattern `from-unit-to-unit-converter`.

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.

F.A.Q.

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

NIST — Physical Measurement and SI Reference — https://www.nist.gov/pml
ISO — Quantities and Units (ISO 80000 series) — https://www.iso.org/standard/67478.html
ISO/IEC 17025 — General requirements for the competence of testing and calibration laboratories — https://www.iso.org/standard/66912.html
IEEE 754 — Standard for Floating-Point Arithmetic — https://standards.ieee.org/standard/754-2019.html
OSHA — Occupational Safety and Health Administration — https://www.osha.gov
NIST SP 811 — Guide for the Use of the International System of Units — https://www.nist.gov/pml/special-publication-811
BIPM SI Brochure (9th edition, 2019) — https://www.bipm.org/en/publications/si-brochure

Further resources

Related tools

External guidance

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: 3517711e2d37

What changed (latest)

v1.0.0 • 2025-11-21 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

Governance

Last updated: Nov 21, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
MINOR: New features or fields that do not change existing outputs for the same inputs.
PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

Verify formulas and unit definitions against primary standards or datasets.
Run golden-case regression suite and edge-case suite.
Record reviewer sign-off with credentials and scope.
Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

Uses exact unit definitions from the Fidamen conversion library.
Internal calculations use double precision; display rounding follows the unit's configured decimal places.
Not a substitute for calibrated instruments in regulated contexts.
Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-21 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: 80fd5c5459e2