Millimeters: conversions & definition
A millimeter is one thousandth of a meter. It is useful for small dimensions and material thickness.
Choose the unit you need
Each row converts one mm. Open a converter to enter any value and see its formula, worked example and reference table. Results below are rounded to 10 significant digits.
| Convert to | Equivalent value | Calculator |
|---|---|---|
| Centimeters (cm) | ≈ 0.1 | Convert mm to cm |
| Meters (m) | ≈ 0.001 | Convert mm to m |
| Kilometers (km) | ≈ 0.000001 | Convert mm to km |
| Inches (in) | ≈ 0.03937007874 | Convert mm to in |
| Feet (ft) | ≈ 0.003280839895 | Convert mm to ft |
| Yards (yd) | ≈ 0.001093613298 | Convert mm to yd |
| Miles (mi) | ≈ 6.213711922e-7 | Convert mm to mi |
| Nautical miles (nmi) | ≈ 5.399568035e-7 | Convert mm to nmi |
| Micrometers (µm) | ≈ 1,000 | Convert mm to µm |
| Megameters (Mm) | ≈ 1e-9 | Convert mm to Mm |
| Nanometers (nm) | ≈ 1,000,000 | Convert mm to nm |
| Gigameters (Gm) | ≈ 1e-12 | Convert mm to Gm |
| Decimeters (dm) | ≈ 0.01 | Convert mm to dm |
| Hectometers (hm) | ≈ 0.00001 | Convert mm to hm |
| Decameters (dam) | ≈ 0.0001 | Convert mm to dam |
| Picometers (pm) | ≈ 1,000,000,000 | Convert mm to pm |
| Terameters (Tm) | ≈ 1e-15 | Convert mm to Tm |
| Femtometers (fm) | ≈ 1e+12 | Convert mm to fm |
| Petameters (Pm) | ≈ 1e-18 | Convert mm to Pm |
| Attometers (am) | ≈ 1e+15 | Convert mm to am |
| Exameters (Em) | ≈ 1e-21 | Convert mm to Em |
| Zeptometers (zm) | ≈ 1e+18 | Convert mm to zm |
| Zettameters (Zm) | ≈ 1e-24 | Convert mm to Zm |
| Yoctometers (ym) | ≈ 1e+21 | Convert mm to ym |
| Yottameters (Ym) | ≈ 1e-27 | Convert mm to Ym |
Keep the quantity consistent
Choose units that represent the same quantity and preserve the measurement conditions. A scale conversion changes the number and unit together; it does not change the physical amount or improve the accuracy of your measurement.
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