Core Links Unit ConverterHPに戻るCompany home
Free web tool

UNIT CONVERTER

Length

1 inch = 25.4 mm exactly.

Result

SI / metric also includes non-SI metric units. Check distinctions such as US and UK units.

Results in other units

Displayed values are rounded. Check the unit type and definition before use.

How to convert, examples and notes

About length conversion

Choose the input and output units, then enter a number. The result updates on this device.

Conversion examples (rounded)

  • 25.4 mm = 1 in
  • 1,000 mm = 39.3700787402 in

Some supported units: nm · µm · mm · cm · m · km (15 units in this category).

1 inch = 25.4 mm exactly.

The nearby list shows the reference unit and up to two rows on either side. Expand it to see every unit. Check SI / metric, imperial / US customary and other definitions before important use.

How do I convert inches to millimetres?

mm = inch × 25.4; inch = mm ÷ 25.4

  • 1 in = 25.4 mm
  • 25.4 mm = 1 in
  • 1 ft = 0.3048 m

Examples are rounded; choose the required display digits in the converter.

Can I enter a drawing dimension such as 1/8?

Fractions and mixed numbers are accepted. Select in as the input unit and enter 1/8 to see its millimetre value. Full-width digits are also supported.

Conversion table for 1 mm

Fixed reference values, rounded to 10 significant digits. Use the converter above for your own value.

UnitName1 mm equals
nmNanometre1,000,000 nm
µmMicrometre1,000 µm
mmMillimetre1 mm
cmCentimetre0.1 cm
mMetre0.001 m
kmKilometre0.000001 km
milMil39.37007874 mil
inInch0.03937007874 in
ftFoot0.003280839895 ft
ydYard0.001093613298 yd
miMile0.0000006213711922 mi
pmPicometre1,000,000,000 pm
ÅAngstrom10,000,000 Å
dmDecimetre0.01 dm
nmiNautical mile0.0000005399568035 nmi