Inches to CM Converter

Convert decimal or fractional inches, feet + inches, or centimeters in either direction. See the exact 2.54 relationship, common fractions, nearby values, a dual-unit visual scale, batch conversions and reusable local history.

Wave186 · exact 2.54 length workflow

Inches ↔ Centimeters — decimals, fractions and feet + inches

Use one field or a tape-measure style value. The factor is exact by definition; choose only how the answer is displayed and rounded.

1 in = exactly 2.54 cm

Inches · smart inputDecimals, fractions, mixed fractions, or feet + inches notation.Centimeters · two-way

Feet + inches

Display precisionNearest inch fraction

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—Centimeters · high precision

—Millimeters

—Meters

—Feet + inches

—Nearest selected fraction

2.54Exact cm per inch

Enter a measurement above.

Dual-unit visual scale

Relative comparison only — not an actual-size on-screen ruler. Use the calibrated Online Ruler for physical screen measurement.

Saved conversions

Nearby values · selected fraction step

Common fractional inches

Batch convert up to 100 measurements

One measurement per line. Decimals, mixed fractions and feet + inches notation are accepted.

Truth boundary: 1 international inch is exactly 2.54 centimeters. The conversion factor is exact, while displayed decimal results may be rounded. Fraction rounding is a presentation choice, not a change to the underlying length. The dual-unit graphic is proportional, not physically calibrated to your screen.

Inches to centimeters without losing the measurement context

Fractions are first-class input

Measurements from rulers, tape measures and product drawings often arrive as 3/8″ or 12 1/2″ rather than decimals. Enter the fraction directly instead of converting it by hand first.

Feet + inches use the same exact factor

Convert the whole measurement to inches, then multiply by 2.54. For example, 5′7″ is 67 inches, so it is exactly 170.18 cm before display rounding.

Keep precision separate from accuracy

More decimal places do not make the original measurement more accurate. Preserve enough digits for the task, then round the final displayed answer to match the source measurement.

Check a drawing or product spec in both systems

Use centimeters, millimeters and meters together when a metric specification mixes units. The nearby-value and fraction tables help catch a misplaced decimal or denominator.

Why 2.54 is exact

The international inch is defined as exactly 25.4 mm, which is exactly 2.54 cm. Any uncertainty comes from the measured object or your rounding choice, not from the conversion factor itself.

Do not use the visual strip as a physical ruler

Browser pixels are not guaranteed to have a fixed real-world size. The strip compares the two unit scales proportionally; physical on-screen measurement requires calibration.