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Woodworking Math

23/64 inch in decimal and mm

Decimal inches

0.359375 in

0.3594 in to four places

Millimetres

9.128125 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: 23/64 in = 23 ÷ 64 = 0.359375 in.
  2. An inch is exactly 25.4 mm, so 0.359375 × 25.4 = 9.128125 mm, or 9.128 mm to three places.
  3. In feet, divide by 12: 0.359375 ÷ 12 = 0.029948 ft. In centimetres, divide the mm by 10: 0.9128125 cm.

23/64 to the nearest 1/8, 1/16, 1/32

A tape or rule marked more coarsely than 64ths can’t show 23/64 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)
1/83/8 in+0.015625+0.397
1/163/8 in+0.015625+0.397
1/323/8 in+0.015625+0.397

Drills, plywood and lumber at 23/64 in

Drills either side of 23/64 in
DrillSizeOff by
9.1 mm0.3583 in−0.0281 mm
9.2 mm0.3622 in+0.0719 mm

Every drill is on the drill bit size chart.

Bits of this size

Sizes either side

FractionDecimalmm
11/32 in0.34375 in8.731 mm
3/8 in0.375 in9.525 mm

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