1 inch equals exactly 2.54 centimeters. This is not an approximation — by international agreement since 1959, the inch is defined as precisely 2.54 cm. There is no rounding in the conversion factor itself, only in how you choose to display the result.
The formula
cm = inches × 2.54
To convert centimeters back to inches, divide by 2.54:
inches = cm ÷ 2.54
Practical examples
Example 1 — Measuring a picture frame
You have a US picture frame labeled 8 × 10 inches. You need the centimeter size to order a custom mat in a European shop.
- 8 × 2.54 = 20.32 cm
- 10 × 2.54 = 25.4 cm
Example 2 — Furniture width
A US furniture listing says a bookcase is 36 inches wide. Your space measures in centimeters.
36 × 2.54 = 91.44 cm
Example 3 — Screen or monitor size
A laptop screen is described as 15.6 inches (measured diagonally). The metric equivalent is:
15.6 × 2.54 = 39.62 cm
Quick reference: inches to centimeters
| Inches | Centimeters |
|---|---|
| 1 in | 2.54 cm |
| 2 in | 5.08 cm |
| 3 in | 7.62 cm |
| 4 in | 10.16 cm |
| 6 in | 15.24 cm |
| 8 in | 20.32 cm |
| 10 in | 25.40 cm |
| 12 in (1 ft) | 30.48 cm |
| 18 in | 45.72 cm |
| 24 in (2 ft) | 60.96 cm |
| 36 in (3 ft / 1 yd) | 91.44 cm |
| 48 in (4 ft) | 121.92 cm |
Common uses for inches-to-cm conversion
- Furniture and décor: US furniture listings use inches; European stores use centimeters. When buying a rug, curtains, or cabinet online, always convert before ordering.
- Screen sizes: Monitor, TV, and phone screen sizes are measured diagonally in inches in US markets and centimeters in some European markets.
- Photo prints: Standard US photo sizes (4×6, 5×7, 8×10) have metric equivalents used in European photo labs.
- Clothing and shoe sizing: US clothing sometimes includes body measurements in inches; European sizing uses centimeters.