Convert Inches (in) to Centimeters (cm)
1 inch equals 2.54 centimeters.
Inch to Centimeter Converter
What Is an Inch?
The inch (in) is a unit of length in the US customary and British imperial systems. Since 1959, it is defined as exactly 25.4 millimeters (2.54 cm). The inch is widely used in the US and UK for screen sizes, paper dimensions, and construction measurements.
What Is a Centimeter?
The centimeter (cm) is a metric unit of length equal to one hundredth of a meter (0.01 m). It is used worldwide for body measurements, clothing sizes, and small-scale dimensions. One centimeter = 10 millimeters.
Inches to Centimeters Formula
The conversion factor is exact by international definition:
centimeters = inches × 2.54 exact
This comes from the 1959 agreement that defined 1 inch = 25.4 mm exactly.
Worked Example
Convert a 55-inch TV screen diagonal to centimeters:
- Multiply: 55 × 2.54 = 139.7 cm
Quick Estimation
For mental math, multiply inches by 2.5 (underestimates by 1.6%). Example: 12 in × 2.5 = 30 cm (exact: 30.48 cm). Close enough for everyday estimates.
Common Use Cases
- Screen sizes: TVs and monitors are sold in inches worldwide but metric countries need cm. A 65-inch TV = 165.1 cm diagonal.
- Paper sizes: US Letter (8.5 × 11 in) = 21.59 × 27.94 cm. A4 (21 × 29.7 cm) ≈ 8.27 × 11.69 in.
- Body measurements: UK/US clothing uses inches for waist, chest, inseam. Converting to cm for international sizing.
- Construction: US lumber and hardware in inches; metric screws and fittings in mm/cm.
Frequently Asked Questions
How many centimeters are in 1 inch?
Exactly 2.54 cm. This is not an approximation — it is the exact international definition since 1959.
How do I convert inches to centimeters without a calculator?
Multiply by 2.5 for a quick estimate (within 1.6%). For better accuracy, multiply by 2.5 and add 1.6% — or just use 2.54.
Why do some countries still use inches?
The US never fully adopted metric. Screen sizes, pipe diameters, and construction materials are sold in inches globally due to US manufacturing dominance.
What common objects are about 1 inch long?
A US quarter coin diameter (24.3 mm ≈ 0.96 in), the width of an adult thumb, or two stacked pennies.
Fractional Inches to Centimeter Chart
Common fractional inch values and their equivalents in cm. Useful for machining, woodworking, drill bits, and precision measurements.
Fractions of an inch (1/64″ to 1″)
| Fraction (in) | Decimal (in) | cm |
|---|---|---|
| 1/64″ | 0.0156 | 0.0397 |
| 1/32″ | 0.0313 | 0.0794 |
| 3/64″ | 0.0469 | 0.1191 |
| 1/16″ | 0.0625 | 0.1588 |
| 5/64″ | 0.0781 | 0.1984 |
| 3/32″ | 0.0938 | 0.2381 |
| 7/64″ | 0.1094 | 0.2778 |
| 1/8″ | 0.1250 | 0.3175 |
| 9/64″ | 0.1406 | 0.3572 |
| 5/32″ | 0.1563 | 0.3969 |
| 11/64″ | 0.1719 | 0.4366 |
| 3/16″ | 0.1875 | 0.4763 |
| 13/64″ | 0.2031 | 0.5159 |
| 7/32″ | 0.2188 | 0.5556 |
| 15/64″ | 0.2344 | 0.5953 |
| 1/4″ | 0.2500 | 0.6350 |
| 17/64″ | 0.2656 | 0.6747 |
| 9/32″ | 0.2813 | 0.7144 |
| 19/64″ | 0.2969 | 0.7541 |
| 5/16″ | 0.3125 | 0.7938 |
| 21/64″ | 0.3281 | 0.8334 |
| 11/32″ | 0.3438 | 0.8731 |
| 23/64″ | 0.3594 | 0.9128 |
| 3/8″ | 0.3750 | 0.9525 |
| 25/64″ | 0.3906 | 0.9922 |
| 13/32″ | 0.4063 | 1.0319 |
| 27/64″ | 0.4219 | 1.0716 |
| 7/16″ | 0.4375 | 1.1113 |
| 29/64″ | 0.4531 | 1.1509 |
| 15/32″ | 0.4688 | 1.1906 |
| 31/64″ | 0.4844 | 1.2303 |
| 1/2″ | 0.5000 | 1.2700 |
| 33/64″ | 0.5156 | 1.3097 |
| 17/32″ | 0.5313 | 1.3494 |
| 35/64″ | 0.5469 | 1.3891 |
| 9/16″ | 0.5625 | 1.4288 |
| 37/64″ | 0.5781 | 1.4684 |
| 19/32″ | 0.5938 | 1.5081 |
| 39/64″ | 0.6094 | 1.5478 |
| 5/8″ | 0.6250 | 1.5875 |
| 41/64″ | 0.6406 | 1.6272 |
| 21/32″ | 0.6563 | 1.6669 |
| 43/64″ | 0.6719 | 1.7066 |
| 11/16″ | 0.6875 | 1.7463 |
| 45/64″ | 0.7031 | 1.7859 |
| 23/32″ | 0.7188 | 1.8256 |
| 47/64″ | 0.7344 | 1.8653 |
| 3/4″ | 0.7500 | 1.9050 |
| 49/64″ | 0.7656 | 1.9447 |
| 25/32″ | 0.7813 | 1.9844 |
| 51/64″ | 0.7969 | 2.0241 |
| 13/16″ | 0.8125 | 2.0638 |
| 53/64″ | 0.8281 | 2.1034 |
| 27/32″ | 0.8438 | 2.1431 |
| 55/64″ | 0.8594 | 2.1828 |
| 7/8″ | 0.8750 | 2.2225 |
| 57/64″ | 0.8906 | 2.2622 |
| 29/32″ | 0.9063 | 2.3019 |
| 59/64″ | 0.9219 | 2.3416 |
| 15/16″ | 0.9375 | 2.3813 |
| 61/64″ | 0.9531 | 2.4209 |
| 31/32″ | 0.9688 | 2.4606 |
| 63/64″ | 0.9844 | 2.5003 |
| 1″ | 1.0000 | 2.5400 |
Whole inches (2″ to 12″)
| Inches | cm |
|---|---|
| 2″ | 5.0800 |
| 3″ | 7.6200 |
| 4″ | 10.160 |
| 5″ | 12.700 |
| 6″ | 15.240 |
| 7″ | 17.780 |
| 8″ | 20.320 |
| 9″ | 22.860 |
| 10″ | 25.400 |
| 11″ | 27.940 |
| 12″ | 30.480 |
Bold rows indicate common fractions (1/8, 1/4, 3/8, 1/2, etc.). The conversion factor 1 inch = 25.4 mm is exact by international definition.
Common Inch to Centimeter Conversions
Inches to centimeters Conversion Table
Reference table with common inches to centimeters conversions. All values calculated with high precision.
Inches to Centimeters Table
1 to 100000
Centimeters to Inches Table
0.001 to 5
Centimeters to Inches Table
10 to 1000000
Looking for the reverse? Convert Centimeter to Inch
Related Length, Height & Distance Converters
Explore other length, height & distance conversion tools:
Related in other categories:
- Sq Feet to Sq Meters — Area uses squared length units
