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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.

Inches (fraction)
9/16 in

13.88 mm ≈ 9/16 in

Exact size 0.546 in · 9/16 in is 0.41 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 13.88 ÷ 25.4 = 0.5465 in
  2. Count the 1/16 in marks 0.5465 × 16 = 8.74 → nearest mark: 9
  3. Simplify the fraction 9/16 in = 9/16 in
Picture it

13.88 mm is 0.546 in, between marks. The nearest mark is 9/16 in (0.41 mm over).

Nearest mark Exact size

Nearby values

Millimeters Inches (fraction) Exact Centimeters
10.88 mm 7/16 in 0.43 1.09
11.88 mm 7/16 in 0.47 1.19
12.88 mm 1/2 in 0.51 1.29
13.88 mm 9/16 in 0.55 1.39
14.88 mm 9/16 in 0.59 1.49
15.88 mm 5/8 in 0.63 1.59
16.88 mm 11/16 in 0.66 1.69