A single inch
- Inches
- 1
Result Centimeters: 2.54
- 1 in × 2.54 = 2.54 cm
Since 1959 the inch has been defined as exactly 2.54 centimetres, so no rounding is involved at all.
Inches to cm Converter
To convert inches to centimetres, multiply by 2.54. That factor is exact by international definition, not a rounded approximation. For example, a 15.6-inch laptop screen measures 15.6 × 2.54 = 39.624 cm across its diagonal, and a 12-inch ruler is 30.48 cm long.
Inches to Centimeters conversion table
| in | cm |
|---|---|
| 1 | 2.54 |
| 2 | 5.08 |
| 5 | 12.7 |
| 10 | 25.4 |
| 20 | 50.8 |
| 25 | 63.5 |
| 50 | 127 |
| 100 | 254 |
| 250 | 635 |
| 500 | 1,270 |
| 1,000 | 2,540 |
About this tool
Product listings from the United States quote sizes in inches, while most of the world measures in centimetres. This converter turns an inch figure into centimetres as you type, which helps when comparing TV and monitor diagonals, checking clothing measurements, reading furniture dimensions or following a woodworking plan. It also shows the multiplication it used so you can verify the figure by hand. The factor 2.54 is exact, so any difference you see against another source comes from rounding on their side. One limit: fractional inch marks such as 3 7/16 must be typed as decimals (3.4375), since the field accepts numbers only.
How to use it
Type the length in inches
Enter the measurement in the inches field. Decimals work, so 5.75 stands for five and three-quarter inches.
Read the centimetre value
The result in centimetres updates while you type, together with the multiplication behind it.
Swap or share
Use Swap to go from centimetres back to inches, or Share to send a link that reopens the same value.
Examples
A 12-inch ruler
- Inches
- 12
Result Centimeters: 30.48
- 12 in × 2.54 = 30.48 cm
Twelve inches make one foot, and a standard school ruler therefore measures 30.48 cm end to end.
A 15.6-inch laptop screen
- Inches
- 15.6
Result Centimeters: 39.624
- 15.6 in × 2.54 = 39.624 cm
Screen sizes are diagonal measurements, so a 15.6-inch display is about 39.6 cm from corner to corner.
How it is calculated
cm = in × 2.54
in- length in international inches
cm- length in centimetres
The 1959 international yard and pound agreement fixed the yard at exactly 0.9144 metres. A yard holds 36 inches, so one inch is 0.9144 ÷ 36 = 0.0254 m, which is 2.54 cm. Because the factor is defined rather than measured, the result is exact to however many digits you enter; only the display rounds it.
When not to use it
- Old US survey drawings may use the survey inch, which differs from the international inch by two parts per million.
- Inch-based thread pitches and wire gauges are lookup standards, not plain lengths, so converting the label number gives a meaningless result.
Common mistakes
- Dividing by 2.54 instead of multiplying gives a figure about 6.5 times too small.
- Typing 3 1/2 as 3.12 instead of 3.5 shifts the answer by almost a centimetre.
Frequently asked questions
Why is an inch exactly 2.54 cm?
In 1959 the United States, United Kingdom, Canada, Australia, New Zealand and South Africa agreed to define the yard as 0.9144 metres. Dividing by 36 inches per yard gives exactly 2.54 cm per inch.
How many inches are in a centimetre?
One centimetre is about 0.3937 inches, the reciprocal of 2.54. Use the swap direction to convert centimetres to inches directly.
How do I convert a fraction like 5 3/8 inches?
Turn the fraction into a decimal first: 3 ÷ 8 = 0.375, so 5 3/8 inches is 5.375. Entering that gives 13.6525 cm.
How tall is 5 feet 10 inches in centimetres?
Five feet is 60 inches, so 5 ft 10 in is 70 inches. Multiplying by 2.54 gives 177.8 cm.
Does a 55-inch TV measure 55 inches wide?
No. TV and monitor sizes are diagonal. A 55-inch screen is 139.7 cm corner to corner, while a 16:9 panel of that size is only about 121.8 cm wide.
Cite this tool
Using this tool in an assignment, article or report? Copy a citation, or a link for your website.
APA
Tools Directory Editorial Team. (2026, October 18). Inches to cm Converter. Tools Directory. Retrieved October 26, 2026, from https://tools.milunir.com/converters/length/inches-to-cm-converter/
MLA
Tools Directory Editorial Team. “Inches to cm Converter.” Tools Directory, 18 Oct. 2026, https://tools.milunir.com/converters/length/inches-to-cm-converter/. Accessed 26 Oct. 2026.
Chicago
Tools Directory Editorial Team. “Inches to cm Converter.” Tools Directory. Last modified October 18, 2026. Accessed October 26, 2026. https://tools.milunir.com/converters/length/inches-to-cm-converter/.
Link
<a href="https://tools.milunir.com/converters/length/inches-to-cm-converter/">Inches to cm Converter – Tools Directory</a>