1 in to mm
1 inch in millimeters
1 in = 25.4 mm
mm = in × 25.4
1 inch is 25.4 millimeters. To get there, multiply by 25.4.
Values either side
| Inches | Millimeters |
|---|---|
| 0.5 in | 12.7 |
| 1 in ← | 25.4 |
| 1.5 in | 38.1 |
| 2 in | 50.8 |
| 2.5 in | 63.5 |
| 3 in | 76.2 |
How the conversion works
The relationship is mm = in × 25.4. Both units measure length, so the conversion is a fixed factor that never changes. The figure is exact rather than approximate: since the international yard and pound agreement of 1959, an inch is defined as exactly 25.4 millimetres and a pound as exactly 0.45359237 kilograms, and every other imperial and US customary unit here is derived from those two.
Common questions
- What is 1 in in millimeters?
- 1 in is 25.4 mm.
- How do you convert inches to millimeters?
- Multiply by 25.4.
Related pages
- Inches to millimeters Full table and converter
- 1 mm to in The other direction
- 0.5 in to mm 12.7 mm
- 1.5 in to mm 38.1 mm
- 2 in to mm 50.8 mm
- 2.5 in to mm 63.5 mm
- 3 in to mm 76.2 mm
Sources
- Guide for the Use of the International System of Units (SP 811) — NIST (Public domain (US Government))
- The International System of Units (SI Brochure) — Bureau International des Poids et Mesures
- Calculated on this page — At One Place