What is a Centimeter (cm)?
A centimeter is a precise metric unit of length used worldwide in the International System of Units (SI).
- It is exactly 1/100 of a meter.
- It is equal to exactly 10 millimeters.
- It is equal to exactly 1/2.54 of an inch.
What is an Inch (in)?
An inch is a standard unit of length used primarily in the United States customary and imperial measurement systems.
- 1 inch is exactly 1/12 of a foot.
- 1 inch is exactly 1/36 of a yard.
- 1 inch is equal to exactly 2.54 centimeters.
How to Convert cm to inches
Because one inch is exactly 2.54 centimeters, you only need to remember one rule to get a perfectly accurate conversion:
Take your exact number in centimeters and divide it by 2.54.
Example 1:
If you need to know exactly what 20 cm is in inches:
- 20 ÷ 2.54 = 7.874016 inches
Example 2:
To convert exactly 50 cm to inches:
- 50 ÷ 2.54 = 19.685039 inches
CM to Inches Decimal Chart (For Math & DIY)
For projects requiring strict precision, here is the exact mathematical conversion table:
| Centimeters (cm) | Exact Inches (in) |
|---|---|
| 0.01 cm | 0.003937 in |
| 0.1 cm | 0.039370 in |
| 1 cm | 0.393701 in |
| 2 cm | 0.787402 in |
| 3 cm | 1.181102 in |
| 4 cm | 1.574803 in |
| 5 cm | 1.968504 in |
| 6 cm | 2.362205 in |
| 7 cm | 2.755906 in |
| 8 cm | 3.149606 in |
| 9 cm | 3.543307 in |
| 10 cm | 3.937008 in |
| 20 cm | 7.874016 in |
| 30 cm | 11.811024 in |
| 40 cm | 15.748031 in |
| 50 cm | 19.685039 in |
| 60 cm | 23.622047 in |
| 70 cm | 27.559055 in |
| 80 cm | 31.496063 in |
| 90 cm | 35.433071 in |
| 100 cm | 39.370079 in |
How to Convert cm into “Inches and Fractions” (For Sewing & Woodworking)
If you are measuring waistlines for clothes, or cutting wood for a DIY project, a decimal like “7.87 inches” isn’t helpful on a standard measuring tape. You need inches and fractions (like 1/2″, 1/4″, or 1/8″). Here is the easy two-step process:
Let’s convert 20 cm to inches and fractions:
Step 1: Find the Whole Inches Divide your centimeters by 2.54.
- 20 ÷ 2.54 = 7.874 inches.
- The whole number is your inches. So, you have 7 inches.
Step 2: Find the Fraction Take the leftover decimal (0.874) and multiply it by 16 (since standard tape measures are divided into 16ths of an inch).
- 0.874 × 16 = 13.98 (which rounds up to 14).
- Your fraction is 14/16, which simplifies to 7/8.
Result: 20 cm is approximately 7 and 7/8 inches (7 7/8″).
Common Measurements Conversion Chart
For buying clothes online, measuring furniture, or checking laptop screen sizes, here are exact conversions for common everyday measurements:
| Centimeters (cm) | Decimal Inches (in) | Standard Tape Measure (in) |
|---|---|---|
| 10 cm | 3.94 in | 3 15/16″ |
| 15 cm | 5.91 in | 5 7/8″ |
| 25 cm | 9.84 in | 9 13/16″ |
| 30 cm | 11.81 in | 11 13/16″ |
| 50 cm | 19.69 in | 19 11/16″ |
| 75 cm | 29.53 in | 29 1/2″ |
| 100 cm | 39.37 in | 39 3/8″ |
| 120 cm | 47.24 in | 47 1/4″ |
| 150 cm | 59.06 in | 59 1/16″ |
FAQs
How many inches are in 1 centimeter?
Because a centimeter is much smaller than an inch, 1 cm is equal to a fraction of an inch. Specifically, 1 ÷ 2.54 = 0.393701 inches.
How many centimeters are in 1 inch?
One inch is precisely equal to 2.54 centimeters.
How do I accurately convert 10 cm to inches?
Using the exact conversion rate, divide 10 by 2.54.
10 ÷ 2.54 = 3.937008 inches.