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Woodworking Math

59/64 inch in decimal and mm

Decimal inches

0.921875 in

0.9219 in to four places

Millimetres

23.415625 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: 59/64 in = 59 ÷ 64 = 0.921875 in.
  2. An inch is exactly 25.4 mm, so 0.921875 × 25.4 = 23.415625 mm, or 23.416 mm to three places.
  3. In feet, divide by 12: 0.921875 ÷ 12 = 0.076823 ft. In centimetres, divide the mm by 10: 2.3415625 cm.

59/64 to the nearest 1/8, 1/16, 1/32

A tape or rule marked more coarsely than 64ths can’t show 59/64 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)
1/87/8 in−0.046875−1.191
1/1615/16 in+0.015625+0.397
1/3215/16 in+0.015625+0.397

Drills, plywood and lumber at 59/64 in

Drills either side of 59/64 in
DrillSizeOff by
23 mm0.9055 in−0.4156 mm
23.5 mm0.9252 in+0.0844 mm

Every drill is on the drill bit size chart.

Bits of this size

Sizes either side

FractionDecimalmm
29/32 in0.90625 in23.019 mm
15/16 in0.9375 in23.813 mm

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