Length converter
Millimeter to Inch Converter
Convert mm to in or reverse with one click. Type a value below for an instant result.
Millimeter mm
Inch in
mm → in · runs in your browser, no server
How to convert millimeter to inch
Millimeter (mm) and Inch (in) both measure length. Whether you are studying, traveling, cooking, or working on a project, converting between them should be fast and accurate.
This page converts millimeter to inch — the direction you need when a product, map, or recipe uses metric but you think in US or UK customary units.
The standard relationship used on this page means that 1 millimeter equals 0.039370 in. Enter any number in the calculator — use the swap button to reverse the direction without leaving the page.
Converting 25 mm gives 0.984251 in. This is a practical reference when switching between millimeter and inch for travel distances, screen sizes, furniture dimensions, and construction plans.
Need the opposite direction? Use the hub converter on the length converters page.
When you'll use this
- Reading a metric drill bit, screw, or bolt diameter (e.g., M6 = 6 mm) and finding the closest inch-based US tool
- Converting a camera lens filter thread size or phone screen thickness spec given in millimeters
- Checking a European precision machining or engineering drawing dimension against US inch-based tooling
- Converting rainfall totals reported in mm on international weather sites to the inches used on US forecasts
- Matching a watch case thickness or jewelry measurement given in mm to a US buyer's mental inch scale
Practical note
This page is a favorite among DIYers and machinists working across metric and imperial tool sets: a 6 mm hex key converts to about 0.236 inches — close to, but not exactly, a 1/4-inch (0.25 in) key, which is why swapping metric and imperial tools on the same bolt can strip a head if you grab the near-miss size. Photographers use it for lens filter threads, and meteorology fans use it to translate European or Asian rainfall reports (given in millimeters) into the inch-based totals shown on US weather apps — a "50 mm" rain event converts to just under 2 inches, a genuinely heavy downpour by US standards.
Tips
- US tools are typically sized in fractions of an inch (1/16, 1/32, 1/64), so round the converted mm value to the nearest common fraction before shopping for a matching drill bit or wrench.
- A metric M6 bolt (6 mm nominal diameter) is close to, but not identical to, a 1/4-inch bolt — always verify thread pitch too, not just diameter.
- For rainfall, 25.4 mm equals exactly 1 inch, so a "25 mm" storm total is almost exactly a 1-inch rainfall day on a US-style forecast.
mm to in conversion table
| mm | in |
|---|---|
| 1 | 0.039370 |
| 2 | 0.078740 |
| 5 | 0.196850 |
| 10 | 0.393700 |
| 25 | 0.984251 |
| 50 | 1.968503 |
| 100 | 3.937007 |
| 150 | 5.905511 |
| 200 | 7.874015 |
in to mm conversion table
Or click the swap button in the converter to switch from in to mm.
| in | mm |
|---|---|
| 1 | 25.4 |
| 2 | 50.8 |
| 6 | 152.4 |
| 12 | 304.8 |
| 24 | 609.6 |
| 36 | 914.4 |
| 48 | 1219.2 |
| 60 | 1524 |
| 72 | 1828.8 |
Frequently asked questions
How many inches are in 1 millimeter? +
One millimeter equals 0.039370 in. Use the converter above for any value — results are calculated locally with full precision.
How do I convert mm to in? +
Use the formula: in = mm × 0.039370. Enter your value in the calculator and the result appears instantly. Click the swap button to convert in back to mm.
How many millimeters are in 1 inch? +
One inch equals 25.4 mm. Swap the converter direction to work backwards from in to mm.
What is 10 mm in in? +
10 mm is 0.393700 in. See the conversion table on this page for more common values.
When would I convert millimeter to inch? +
This conversion is useful for travel distances, screen sizes, furniture dimensions, and construction plans. ConvertHub runs entirely in your browser — no data is uploaded to any server.
Is millimeter to inch the same as inch to millimeter? +
They are inverse operations. This page focuses on mm → in with examples and tables for that direction. For in → mm, use our separate inch to millimeter converter page.