Convert inches to millimeters
mm = in × 25.4. 2 in = 50.8 mm.
mm = in × 25.4 — 1 in is 25.4 mm
Common values, converted exactly
| inches (in) | millimeters (mm) |
|---|---|
| 0.125 in (1/8) | 3.175 mm |
| 0.25 in (1/4) | 6.35 mm |
| 0.5 in (1/2) | 12.7 mm |
| 0.75 in (3/4) | 19.05 mm |
| 1 in (1) | 25.4 mm |
| 1.5 in (1 1/2) | 38.1 mm |
| 2 in (2) | 50.8 mm |
| 3 in (3) | 76.2 mm |
| 4 in (4) | 101.6 mm |
| 6 in (6) | 152.4 mm |
| 12 in (12) | 304.8 mm |
| 24 in (24) | 609.6 mm |
To convert inches to millimeters, apply mm = in × 25.4. For example, 2 in = 50.8 mm, and 1 in is 25.4 mm.
One inch is exactly 25.4 mm. Fractional inches are the usual answer in workshop use, so the table below gives the nearest 1/16 alongside each decimal, marking with ≈ any value that falls between the marks rather than on one.
Everything on this page is computed in your browser from the exact definitions above — the table is not a stored list of pre-rounded answers, and neither is the converter. For a unit not covered here, the full unit converter handles length, weight, volume, temperature and cooking measures.
How many millimeters is 2 in?
2 in = 50.8 mm. mm = in × 25.4, so any amount converts the same way — the table on this page lists the values most often looked up.
What is the formula for converting inches to millimeters?
mm = in × 25.4. One inch is exactly 25.4 mm. Fractional inches are the usual answer in workshop use, so the table below gives the nearest 1/16 alongside each decimal, marking with ≈ any value that falls between the marks rather than on one.
Is the inches to millimeters conversion exact?
The underlying relationship is an exact definition, not a measurement. The decimal factor shown (25.4 mm) is a rounding of it, so results here are given to six significant figures — enough for any practical use, and you can see the exact definition above.
How do I convert millimeters back to inches?
Use the reverse of the same relationship; the mm to inches page has its own table and converter.