Inches to Millimeters converter (in → mm)
114,160 in = 2,899,664 mm. 1 in = 25.4 mm. Type any value below for an instant answer, or find your number in the conversion chart.
in to mm formula
Worked example: 11 in = 279.4 mm. The defining value behind this factor is documented on our length & distance standards page.
Inches to Millimeters chart
Includes standard reference values plus the specific numbers people search for most.
| Inches (in) | Millimeters (mm) |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 7 in | 177.8 mm |
| 8 in | 203.2 mm |
| 9 in | 228.6 mm |
| 10 in | 254 mm |
| 11 in | 279.4 mm |
| 12 in | 304.8 mm |
| 15 in | 381 mm |
| 18 in | 457.2 mm |
| 20 in | 508 mm |
| 22 in | 558.8 mm |
| 23 in | 584.2 mm |
| 24 in | 609.6 mm |
| 25 in | 635 mm |
| 28 in | 711.2 mm |
| 30 in | 762 mm |
| 32 in | 812.8 mm |
| 35 in | 889 mm |
| 40 in | 1,016 mm |
| 42 in | 1,066.8 mm |
| 45 in | 1,143 mm |
| 50 in | 1,270 mm |
| 75 in | 1,905 mm |
| 80 in | 2,032 mm |
| 100 in | 2,540 mm |
| 150 in | 3,810 mm |
| 200 in | 5,080 mm |
| 250 in | 6,350 mm |
| 500 in | 12,700 mm |
| 1000 in | 25,400 mm |
Most-searched in to mm answers
11 in to mm
279.4 mm6 in to mm
152.4 mm7 in to mm
177.8 mm10 in to mm
254 mm15 in to mm
381 mm4 in to mm
101.6 mm12 in to mm
304.8 mm2 in to mm
50.8 mm30 in to mm
762 mm45 in to mm
1,143 mm22 in to mm
558.8 mm40 in to mm
1,016 mmWhen to convert in to mm
Use inches to millimeters for fasteners, screens, tools, machining and product specifications.
- ▸Match an inch bolt, pipe or drill size with a metric measurement.
- ▸Convert product thickness or screen dimensions into millimeters.
Common mistakes
- ✕One inch is exactly 25.4 mm; fractional-inch inputs should first be written as decimals.
- ✕Mixing US and international inches — since 1959 all inches are 25.4 mm exactly; older US "survey foot" values are slightly different.
- ✕Off-by-decimal errors: 1 cm = 10 mm, 1 m = 100 cm — a misplaced decimal turns a in into a wildly wrong mm.
- ✕Confusing feet with yards (1 yd = 3 ft) in DIY calculations.
- ✕The US survey foot is not the international foot. The US survey foot was 1200/3937 m (about 0.30480061 m) — roughly 2 parts per million longer than the international foot of 0.3048 m. NIST retired it for new work at the end of 2022, but old survey and land records still use it. Over a mile the difference is about 3 mm; over 100 km it is about 200 mm, which matters in surveying and geodesy and nowhere else.
Regional usage & source
Metric units (mm, cm, m, km) are used in most of the world. Imperial units (in, ft, yd, mi) are standard in the US and still common in the UK for road distances and human height.
Reference: Conversion factors are defined by the International System of Units (SI) as maintained by the BIPM (bipm.org) and NIST (nist.gov). 1 inch = exactly 0.0254 meters (international yard and pound agreement, 1959).
How these numbers are produced and rounded: methodology.