Convert Centimeters to Inches (cm to inch)

This tool converts length from centimeters (centimetre; cm) to inches (inch; in, ″) using the exact standard 1 in = 2.54 cm. Designed for quick entry, precise rounding (0–10 decimals), one-click copying, and an easy link to the reverse inches → centimeters page.

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How to use

1. Enter the length in centimeters in the input field.
2. Click Convert to compute inches (in).
3. Optionally set Decimal Places (0–10) to control rounding of the result.
4. Use Copy Result to place the computed value on your clipboard.
5. Use the Swap link to open the reverse inches → centimeters calculator.
6. Use Clear All to reset inputs and messages; the calculation line shows the exact formula used.

Units and definitions

Centimeter (cm): A decimal fraction of the metre in the SI system; 1 m = 100 cm and 1 cm = 10 mm. Relationship in this calculator: 1 cm = 1/2.54 in ≈ 0.393701 in. Common spelling variants: centimeter (US), centimetre (UK). System: SI (accepted unit derived from the metre). Typical use: everyday dimensions, consumer product specs, body measurements.

Inch (in or ″): A US customary and Imperial length unit defined exactly by the 1959 agreement as 1 in = 2.54 cm (exact) = 25.4 mm (exact). Relationship in this calculator: 1 in = 2.54 cm. Subdivision: 1 in = 1/12 ft. System: Imperial/US customary. Typical use: hardware, woodworking, displays (screen size), and legacy technical drawings.

Visual comparison of a centimeter and an inch

Centimeters to Inches — what this online calculator does

Converts length from centimeters (centimetre; cm) to inches (inch; in, ″) using the exact standard 1 in = 2.54 cm. Designed for quick entry, precise rounding (0–10 decimals), one-click copying, and an easy link to the reverse inches → centimeters page.

Typical precision: 2–3 decimals for most tasks (e.g., 10 cm → 3.94 in). The math is exact; rounding is applied only to the displayed result.

How to use

1. Enter a value in centimeters in the input field.
2. Click Convert to compute inches.
3. Adjust Decimal Places (0–10) to control rounding.
4. Click Copy Result to copy the output to your clipboard.
5. Use Swap to open the reverse inches → centimeters calculator.
6. Click Clear All to reset inputs, output, and the calculation line. The calculation line shows the exact formula used.

Units and definitions

Centimeter (centimetre; cm) — SI unit derived from the metre. 1 m = 100 cm; 1 cm = 10 mm = 0.01 m. In this calculator: 1 cm = (1 / 2.54) in (exact) ≈ 0.393701 in. System: SI (metric). Common spellings: centimeter (US), centimetre (UK). Typical use: product specs, body measurements, small components.

Inch (in, ″) — Imperial/US customary length unit defined exactly since 1959 as 1 in = 25.4 mm = 2.54 cm = 0.0254 m. Relation in this calculator: 1 in = 2.54 cm (exact). Also 1 in = 1/12 ft = 1/36 yd. System: Imperial and US customary. Typical use: hardware, woodworking, display sizes, and legacy engineering drawings; often expressed in fractions (e.g., 1/8 in, 1/16 in) or decimals.

Conversion formula

inches (in) = centimeters (cm) ÷ 2.54

centimeters (cm) = inches (in) × 2.54

Source: NIST Handbook 44, Appendix C — General Tables of Units of Measurement

Conversion table (cm → in)

Real-world, exact-size examples

• US Letter paper: 8.5 × 11 in = 21.59 × 27.94 cm
• US Legal paper: 8.5 × 14 in = 21.59 × 35.56 cm
• ISO A4 paper: 21.0 × 29.7 cm = 8.268 × 11.693 in
• Credit card (ISO/IEC 7810 ID-1): 8.56 × 5.398 cm = 3.370 × 2.126 in
• Compact disc (CD) diameter: 12.0 cm = 4.724 in
• US quarter (coin) diameter: 0.955 in = 2.426 cm
• AAA battery (IEC R03) length × diameter: 4.45 × 1.05 cm = 1.752 × 0.413 in
• Rack unit (1U) height: 1.75 in = 4.445 cm
• 19-inch rack panel width: 19.00 in = 48.26 cm
• Index card (3 × 5): 3.00 × 5.00 in = 7.62 × 12.70 cm

What’s your use case for this calculator, and what features would help you (e.g., fraction input, mixed units, batch conversion)? Share your scenario in the comments.

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