How Many mm Is 1 Inch?

Answer
25.4 mm = 1 in

The international inch is defined as exactly 25.4 mm, so no rounding is involved: mm = inches × 25.4 and inches = mm ÷ 25.4. 1 mm = 0.0393701 in.

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    Inches to mm and cm table

    inmmcm
    1 in25.42.54
    2 in50.85.08
    3 in76.27.62
    4 in101.610.16
    5 in12712.7
    6 in152.415.24
    8 in203.220.32
    10 in25425.4
    12 in304.830.48
    24 in609.660.96
    36 in914.491.44

    1 in = 25.4 mm exactly (NIST SP 811). 12 in = 1 ft = 304.8 mm.

    Frequently asked questions

    How many inches is 1 mm?

    1 mm = 0.0393701 in, roughly 1/25 of an inch.

    How many cm is 1 inch?

    Exactly 2.54 cm.

    Open the full calculator: Length Converter: mm to Inches (with Fractions), Feet and Miles →