20 mm to Inches

Answer
0.787402 in
20 mm = 0.787402 in ≈ 25/32 in

20 millimeters equals 0.787402 inches, close to but a bit less than 13/16 inch (0.8125 in). It is a familiar size in watchmaking, where a 20mm lug width fits the vast majority of standard watch straps and bands, and it is also a common metric socket size. At 1/64 inch precision the nearest fraction is 25/32 in, a touch smaller than the 13/16 in rounding used at 1/16 inch.

Try another mm value
Decimal inches
0.787402"
Nearest 1/64
25/32"
Centimeters
2 cm

Related values

ValueResult
Decimal inches0.787402 in
Nearest 1/16 in13/16 in
Nearest 1/32 in25/32 in
Nearest 1/64 in25/32 in
Centimeters2 cm

How the conversion works

  1. Divide by 25.4. Since one inch equals exactly 25.4 mm, dividing by 25.4 converts any millimeter figure to inches. For 20 mm: 20 ÷ 25.4 = 0.787402 inches, a decimal that keeps repeating past the sixth digit.
  2. Round to a fraction. Multiply 0.787402 by 64 to get 50.394, then round to the nearest whole number, 50. That gives the unreduced fraction 50/64.
  3. Simplify and read the answer. 50 and 64 share a greatest common divisor of 2, so 50/64 simplifies to 25/32 in. At 1/16 in precision the same value rounds instead to 13/16 in, which is why both fractions appear on different reference charts.

Frequently Asked Questions

20 mm equals 0.787402 inches. At 1/16 in precision that rounds to 13/16 in, and at the finer 1/64 in precision it comes out to 25/32 in, closer to the true decimal value.

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