5/16 Inch as a Decimal

Answer
0.3125 in
5/16 in = 0.3125 in = 7.9375 mm

5/16 inch is a fine gradation between 1/4 inch (0.25 in) and 3/8 inch (0.375 in) on a tape measure or machinist rule. As a decimal it equals 0.3125 inches, or 7.9375 millimeters. It is a very common bolt head and socket size, and it doubles as the standard tap drill for a 3/8-16 machine thread, so it shows up constantly on mechanics' and machinists' benches.

Try another fraction
/
Decimal
0.3125
Millimeters
7.9375 mm

Related values

ValueResult
Decimal0.3125 in
Millimeters7.9375 mm
Centimeters0.7937 cm
Feet0.026042 ft

How the conversion works

  1. Divide. Divide the numerator (5) by the denominator (16) to convert the fraction into a decimal.
  2. Decimal result. 5 ÷ 16 = 0.3125. This is an exact, terminating decimal since 16 is a power of two.
  3. Convert to mm. Multiply the decimal by 25.4, the number of millimeters in one inch: 0.3125 × 25.4 = 7.9375 mm, useful when matching a metric drawing or drill bit to an imperial part.

Frequently Asked Questions

5/16 equals 0.3125 as a decimal. Divide the numerator, 5, by the denominator, 16, to get this result. It is a fine gradation between 1/4 inch and 3/8 inch on a tape measure or machinist rule.

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