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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
6.35 mm

1/4 in = 6.35 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 1/4 in = 0.25 in
  2. Multiply by 25.4 0.25 × 25.4 = 6.35 mm
Picture it

The 1/4 in mark is 6.35 mm from the end of the tape.

Nearby values

Inches Millimeters Centimeters Inches
1/16 in 1.59 mm 0.16 0.06
1/8 in 3.18 mm 0.32 0.13
3/16 in 4.76 mm 0.48 0.19
1/4 in 6.35 mm 0.64 0.25
5/16 in 7.94 mm 0.79 0.31
3/8 in 9.53 mm 0.95 0.38
7/16 in 11.11 mm 1.11 0.44

Printed from rocketcalc.io/length/inch-fractions-to-mm/1-4