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Fractional inches to millimeters

Convert tape-measure fractions like 3/8 or 1 5/16 inch to millimeters, with the math shown step by step.

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Millimeters
38.1 mm

1 1/2 in = 38.1 mm

Also equals

How it works

mm = in × 25.4

Turn the fraction into a decimal first: divide the top number by the bottom number and add any whole inches. One inch is exactly 25.4 millimeters, so multiply by 25.4.

  1. Turn the fraction into a decimal 1 1/2 in = 1.5 in
  2. Multiply by 25.4 1.5 × 25.4 = 38.1 mm
Picture it

The 1 1/2 in mark is 38.1 mm from the end of the tape.

Nearby values

Inches Millimeters Centimeters Inches
1 5/16 in 33.34 mm 3.33 1.31
1 3/8 in 34.93 mm 3.49 1.38
1 7/16 in 36.51 mm 3.65 1.44
1 1/2 in 38.1 mm 3.81 1.5
1 9/16 in 39.69 mm 3.97 1.56
1 5/8 in 41.28 mm 4.13 1.63
1 11/16 in 42.86 mm 4.29 1.69

Printed from rocketcalc.io/length/inch-fractions-to-mm/1-1-2