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Woodworking Math

11/16 inch in decimal and mm

Decimal inches

0.6875 in

Millimetres

17.4625 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: 11/16 in = 11 ÷ 16 = 0.6875 in.
  2. An inch is exactly 25.4 mm, so 0.6875 × 25.4 = 17.4625 mm, or 17.463 mm to three places.
  3. In feet, divide by 12: 0.6875 ÷ 12 = 0.057292 ft. In centimetres, divide the mm by 10: 1.74625 cm.
  4. The same size in finer steps: 11/16 = 22/32 = 44/64. A tape marked in 16ths, 32nds or 64ths shows it at those marks.

11/16 to the nearest 1/8

A tape or rule marked more coarsely than 16ths can’t show 11/16 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+0.0625+1.588

Drills, plywood and lumber at 11/16 in

Drills either side of 11/16 in
DrillSizeOff by
17 mm0.6693 in−0.4625 mm
17.5 mm0.689 in+0.0375 mm

Every drill is on the drill bit size chart.

Bits of this size

Sizes either side

FractionDecimalmm
43/64 in0.671875 in17.066 mm
45/64 in0.703125 in17.859 mm

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