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Woodworking Math

47/64 inch in decimal and mm

Decimal inches

0.734375 in

0.7344 in to four places

Millimetres

18.653125 mm

From the standard, the international inch, 25.4 mm exactly

The math

  1. A fraction is its top number divided by its bottom number: 47/64 in = 47 ÷ 64 = 0.734375 in.
  2. An inch is exactly 25.4 mm, so 0.734375 × 25.4 = 18.653125 mm, or 18.653 mm to three places.
  3. In feet, divide by 12: 0.734375 ÷ 12 = 0.061198 ft. In centimetres, divide the mm by 10: 1.8653125 cm.

47/64 to the nearest 1/8, 1/16, 1/32

A tape or rule marked more coarsely than 64ths can’t show 47/64 exactly. The nearest marks, and how far off each is (plus means the mark is bigger; a size exactly halfway goes to the bigger mark):

NearestMarkOff by (in)Off by (mm)
1/83/4 in+0.015625+0.397
1/163/4 in+0.015625+0.397
1/323/4 in+0.015625+0.397

Drills, plywood and lumber at 47/64 in

Drills either side of 47/64 in
DrillSizeOff by
18.5 mm0.7283 in−0.1531 mm
19 mm0.748 in+0.3469 mm

Every drill is on the drill bit size chart.

Bits of this size

Sizes either side

FractionDecimalmm
23/32 in0.71875 in18.256 mm
3/4 in0.75 in19.050 mm

Every size is on the fraction to decimal chart; any other size goes in the fraction to decimal calculator.