Centimeters to Inches – Exact Formula & Fast Table
Convert cm to inches by dividing by 2.54 (the exact, defined number of centimeters per inch). This gives a precise decimal you can round as needed.
Formula
in = cm ÷ 2.54
cm = in × 2.54 (reverse)
Quick Values
1 cm ≈ 0.3937 in · 5 cm ≈ 1.9685 in · 10 cm ≈ 3.9370 in · 20 cm ≈ 7.8740 in · 50 cm ≈ 19.685 in · 100 cm ≈ 39.3701 in.
Example: 32 cm
- Apply formula: 32 ÷ 2.54 = 12.598425...
- Round (2 decimals): 12.60 in
- Result: 32 cm ≈ 12.60 in
Uses
- Product size & packaging specs
- Engineering drawings needing imperial readouts
- Crafts & woodworking layouts
- Screen / device dimension comparisons
Accuracy & Tips
- Use full precision internally; round only for display
- Head shortcut: cm × 0.4 ≈ in (slightly high – refine down ~1.5%)
- Exact: multiply inches by 2.54 to verify reverse
- For fractions: decimal inches × 16 then round for /16" format
More Examples
| cm | in (exact dec) |
|---|
| 1 | 0.3937008 |
| 12 | 4.7244094 |
| 25 | 9.8425197 |
| 30 | 11.8110236 |
| 45 | 17.7165354 |
FAQ
- Why divide by 2.54? Because 1 in = exactly 2.54 cm.
- Is 2.5 close enough? For rough use yes; precise work no.
- How to reverse? Multiply inches by 2.54.
- Fraction from 7.875 in? 7 7/8" (since .875 = 14/16 = 7/8).