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Woodworking Math

2-3/4 inch in decimal and mm

Decimal inches

2.75 in

Millimetres

69.85 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: 2-3/4 in = 2 + 3 ÷ 4 = 2.75 in.
  2. An inch is exactly 25.4 mm, so 2.75 × 25.4 = 69.85 mm, or 69.850 mm to three places.
  3. In feet, divide by 12: 2.75 ÷ 12 = 0.229167 ft. In centimetres, divide the mm by 10: 6.985 cm.
  4. The same size in finer steps: 2-3/4 = 2-6/8 = 2-12/16 = 2-24/32 = 2-48/64. A tape marked in 16ths, 32nds or 64ths shows it at those marks.

Drills, plywood and lumber at 2-3/4 in

Drills either side of 2-3/4 in
DrillSizeOff by
1 in1 in−1.75 in
25 mm0.9843 in−44.85 mm

Every drill is on the drill bit size chart.

Bits of this size

Sizes either side

FractionDecimalmm
2-1/2 in2.5 in63.500 mm
3 in3 in76.200 mm

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