Inches to Millimeters

    Convert inches to millimeters instantly. Enter a value in in, get mm, and use the formula, examples, and conversion table for quick checks.

    From
    To
    1 in = 25.4 mm1 mm = 0.03937 in
    1 in in other units
    cm
    2.54
    m
    0.0254
    km
    2.5400e-5
    ft
    0.083333
    yd
    0.027778
    mi
    1.5783e-5

    How to convert in to mm

    To convert a value from inches (in) to millimeters (mm), enter the number in the converter above. Use the swap control if you need the reverse direction.

    x is the source value in in; y is the result in mm.

    Conversion factor
    Direct factor: 25.4 mm for 1 in. Reverse factor: 0.03937 in for 1 mm.

    Popular conversions

    Quick answers for common in to mm values are available from the related conversion pages.

    Use the related tools section for fixed-value conversions and the reverse direction.

    Common conversion table

    Quick reference table for common in to mm values:

    inmm
    125.4
    5127
    10254
    501,270
    1002,540
    1,00025,400

    About inches

    Inch (in) — One international inch is exactly 2.54 centimeters.

    Common uses: Inches are common for screen sizes, product dimensions, pipe diameters, and US height notation.

    About millimeters

    Millimeter (mm) is a length unit.

    Frequently Asked Questions

    Updated:

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