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Millimeters to fractional inches

Convert millimeters to the nearest 1/16, 1/32 or 1/64 inch, like the marks on a tape measure, with the math shown step by step.

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Inches (fraction)
3/4 in

18.88 mm ≈ 3/4 in

Exact size 0.743 in · 3/4 in is 0.17 mm over

Also equals

How it works

in = mm ÷ 25.4

One inch is exactly 25.4 millimeters, so dividing by 25.4 gives inches as a decimal. To read that on a tape measure, count how many 1/16-inch marks it covers, round to the nearest mark, then simplify the fraction.

  1. Divide by 25.4 to get inches 18.88 ÷ 25.4 = 0.7433 in
  2. Count the 1/16 in marks 0.7433 × 16 = 11.89 → nearest mark: 12
  3. Simplify the fraction 12/16 in = 3/4 in
Picture it

18.88 mm is 0.743 in, between marks. The nearest mark is 3/4 in (0.17 mm over).

Nearest mark Exact size

Nearby values

Millimeters Inches (fraction) Exact Centimeters
15.88 mm 5/8 in 0.63 1.59
16.88 mm 11/16 in 0.66 1.69
17.88 mm 11/16 in 0.7 1.79
18.88 mm 3/4 in 0.74 1.89
19.88 mm 13/16 in 0.78 1.99
20.88 mm 13/16 in 0.82 2.09
21.88 mm 7/8 in 0.86 2.19

Printed from rocketcalc.io/length/mm-to-inch-fractions/18.88