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Converters › Length
Inches to CM Converter
Convert instantly between inches and centimeters — type into either field and both stay in sync. Supports fractional inches (like 5 3/8″) and a dedicated feet-and-inches mode for converting height.
Fractions are supported in the inches field — try “5 3/8” or “1/2”.
Edit either side — feet/inches or centimeters — and the other updates automatically.
Inches to Centimeters: The Exact Conversion
The inch and the centimeter belong to two different measurement systems — imperial and metric — but the relationship between them isn’t an approximation. Since 1959, under the International Yard and Pound Agreement, the inch has been formally defined as exactly 2.54 centimeters. There’s no rounding involved in the definition itself:
1 inch = 2.54 cm (exact) | 1 cm = 0.393701 inches (rounded)
To convert inches to centimeters, multiply by 2.54. To convert centimeters to inches, divide by 2.54. Every calculation on this page — and inside the calculator above — uses this exact 2.54 figure rather than a rounded shortcut, which matters more than it sounds like once you’re working with larger measurements where small rounding errors compound.
How This Calculator Works
- Inches ↔ CM: a live two-way converter — type a value into either field and the other updates instantly. The inches field also accepts fractions (like
5 3/8or3/4), since fractional inches are the standard in carpentry, sewing, and US tape measures. - Feet & Inches ↔ CM: built specifically for height conversions — enter feet and inches (e.g. 5 ft 7 in) to get centimeters, or enter centimeters to get the equivalent in feet and inches.
A visual size-comparison bar beneath the calculator scales with your entered value, giving you an immediate visual sense of the length or height you’ve converted — useful for sanity-checking a result before ordering material or comparing it to something familiar.
Quick Reference: Common Inch-to-CM Conversions
| Inches | Centimeters | Inches | Centimeters |
|---|---|---|---|
| 1 in | 2.54 cm | 7 in | 17.78 cm |
| 2 in | 5.08 cm | 8 in | 20.32 cm |
| 3 in | 7.62 cm | 9 in | 22.86 cm |
| 4 in | 10.16 cm | 10 in | 25.40 cm |
| 5 in | 12.70 cm | 11 in | 27.94 cm |
| 6 in | 15.24 cm | 12 in (1 ft) | 30.48 cm |
Common Fraction-Inch Conversions
Fractional inches show up constantly on US tape measures and in woodworking plans — here’s how the most common ones convert:
| Fraction | Decimal | Centimeters |
|---|---|---|
| 1/8″ | 0.125″ | 0.32 cm |
| 1/4″ | 0.25″ | 0.64 cm |
| 3/8″ | 0.375″ | 0.95 cm |
| 1/2″ | 0.5″ | 1.27 cm |
| 5/8″ | 0.625″ | 1.59 cm |
| 3/4″ | 0.75″ | 1.91 cm |
| 7/8″ | 0.875″ | 2.22 cm |
Height Conversion Chart: Feet & Inches to Centimeters
One of the most common reasons people search for inch-to-cm conversion is to convert a person’s height — here’s a ready-made reference across the typical adult range:
| Feet & Inches | Centimeters | Feet & Inches | Centimeters |
|---|---|---|---|
| 4′10″ | 147.32 cm | 5′9″ | 175.26 cm |
| 5′0″ | 152.40 cm | 5′10″ | 177.80 cm |
| 5′2″ | 157.48 cm | 5′11″ | 180.34 cm |
| 5′4″ | 162.56 cm | 6′0″ | 182.88 cm |
| 5′6″ | 167.64 cm | 6′2″ | 187.96 cm |
| 5′7″ | 170.18 cm | 6′4″ | 193.04 cm |
| 5′8″ | 172.72 cm | 6′6″ | 198.12 cm |
Imperial vs. Metric: A Brief History
The inch traces back to old English and Roman units based on body measurements — historically defined as the width of a thumb, and later standardized against the length of barleycorns. The centimeter, by contrast, is a purely mathematical unit: one hundredth of a meter, itself originally defined as one ten-millionth of the distance from the North Pole to the equator, and now defined via the speed of light. The United States, Liberia, and Myanmar remain the only countries that haven’t fully adopted the metric system for everyday use, which is exactly why inch-to-cm conversion stays a constant, practical need for anyone working across US and international measurements — in trade, manufacturing, science, or travel.
Real-World Applications of Inch-to-CM Conversion
📏 Height, Clothing & Shoe Sizing
International clothing and shoe size charts are built on centimeter measurements, while US sizing and everyday height references use feet and inches — making conversion a near-constant need when shopping internationally or comparing size charts.
🖥️ Screen & TV Sizing
TVs and monitors are marketed by their diagonal screen size in inches worldwide, but mounting brackets, wall space, and shipping dimensions are frequently specified in centimeters — especially outside the US.
🪚 Woodworking & DIY Projects
US tape measures and lumber are marked in inches (often fractional), while many imported tools, hardware, and plans use metric measurements — this calculator’s fraction support exists specifically for this crossover.
🧵 Sewing & Pattern-Making
Fabric is sold by the yard in the US and by the meter almost everywhere else, and sewing patterns frequently mix inch and centimeter measurements within the same document.
📦 Shipping & International Trade
Customs declarations and international shipping labels typically require centimeter dimensions, even when a product was designed and manufactured using inch-based specifications.
⛳ Sports Equipment
Golf club lengths, bicycle frame sizing, and other sports equipment specifications are frequently published in both inches and centimeters depending on the manufacturer’s home market.
Common Mistakes to Avoid
- Rounding too early in multi-step conversions. If you’re converting inches to centimeters and then using that result in another calculation, keep extra decimal places until the final step to avoid compounding rounding errors.
- Confusing centimeters with millimeters. 1 cm equals 10 mm — mixing these up in a technical drawing can throw a measurement off by a factor of 10.
- Misreading fractional inch marks. US tape measures use small tick marks for 1/16″ and even 1/32″ increments — miscounting ticks is a common source of small but costly errors in woodworking.
- Forgetting the exact conversion factor. Using 2.5 instead of 2.54 as a shortcut introduces a small but avoidable error that grows with the size of the measurement.
Frequently Asked Questions
Exactly 2.54 centimeters, by international definition since 1959. It’s not a rounded approximation — it’s the formal definition of the inch.
Divide the centimeter value by 2.54. For example, 100 cm ÷ 2.54 = 39.37 inches.
Yes — the “Inches ↔ CM” mode accepts fractions directly (e.g. “5 3/8” or “3/4”), which is especially useful for US tape measure readings and woodworking plans.
Switch to “Feet & Inches ↔ CM” mode, enter 5 in the feet field and 7 in the inches field, and the calculator returns the equivalent in centimeters — 170.18 cm in this example.
Because the exact relationship runs the other direction — the inch is defined as exactly 2.54 cm, so 1 cm converts to a repeating decimal, approximately 0.393701 inches.
The United States is the largest economy still using inches and feet for everyday measurement, alongside Liberia and Myanmar, which also haven’t fully adopted the metric system.
No — both countries use the same internationally standardized inch, defined as exactly 2.54 cm, since the 1959 international agreement.
It uses the exact 2.54 cm-per-inch definition with full decimal precision, making it suitable for most practical engineering and manufacturing conversions. For certified measurements, always verify against calibrated equipment.
A quick mental shortcut is multiplying by 2.5 instead of 2.54 for a rough estimate — accurate to within about 2% — but always use the exact 2.54 factor for anything requiring precision.
Yes — it’s completely free, with no login and no limit on how many conversions you can run.
Final Thoughts
Converting between inches and centimeters comes down to one exact number — 2.54 — but the practical challenge is usually fractions, mixed feet-and-inches measurements, or keeping precision through a multi-step calculation. This calculator handles all three: a live two-way converter with fraction support, a dedicated height mode for feet-and-inches, and full decimal precision throughout, so whether you’re reading a tape measure or converting a height for an international form, you get an exact answer without doing the arithmetic by hand.
