How Many mm Is 3/4 Inch?

Answer
19.05 mm = 3/4 inch

0.75 × 25.4 = 19.05 mm, exactly. For pipe, 3/4″ is a nominal size (NPS 3/4, DN 20): steel and PVC Schedule 40 pipe has an outside diameter of 1.050 in = 26.67 mm.

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    Nominal pipe size vs. real dimensions

    Nominal sizeFraction in mmOutside diameter (NPS)
    1/2″12.7 mm0.840″ = 21.34 mm
    3/4″19.05 mm1.050″ = 26.67 mm
    1″25.4 mm1.315″ = 33.4 mm
    1 1/4″31.75 mm1.660″ = 42.16 mm
    1 1/2″38.1 mm1.900″ = 48.26 mm
    2″50.8 mm2.375″ = 60.32 mm

    Outside diameters per ASME B36.10 / ASTM D1785 (NPS). Inside diameter depends on the schedule (wall thickness).

    Frequently asked questions

    What is 3/4 inch in cm?

    1.905 cm.

    What metric size is closest to 3/4 inch?

    19 mm; a 19 mm wrench fits a 3/4″ hex.

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