3/8 inch to mm

Decimal: 0.375 inch

3/8 inch (0.375 inch) = 9.525 mm exactly (0.9525 cm). The international inch is 25.4 mm, so multiply the inch value by 25.4.

Millimeters
9.525
Decimal inches
0.3750
Nearest 1/64
3/8 in (exact on 1/64)

The inches fraction result is rounded to the nearest 1/64 fraction.

3/8 inch to mm conversion

3/8 inch (0.375 inch) × 25.4 = 9.525 mm. Reverse: 9.525 ÷ 25.4 = 0.375 in.

3/8 inch to mm calculator

Use the converter at the top. Type a decimal or a fraction (1/16, 3 1/2). Millimeters update from the same engine as the inch to mm hub (1 in = 25.4 mm).

How to convert 3/8 inch to mm

  1. Write the length as a decimal inch if needed: 3/8 in = 0.375 in (0.375 inch).
  2. Multiply by 25.4: 0.375 × 25.4 = 9.525 mm.
  3. Optional centimeters: divide millimeters by 10 → 0.9525 cm.

Nearest metric size

The nearest metric size is 10 mm, 0.475 mm larger than 9.525 mm.

10 mm is 0.475 mm larger than 3/8 inch (9.525 mm). 9 mm is 0.525 mm smaller, so 10 mm is the nearer whole millimeter. 0.375 inch is the decimal form of 3/8.

3/8 inch is 9.525 mm, not a whole millimeter. Whole-millimeter neighbors:

  • 9 mm is 0.525 mm smaller than 3/8 inch.
  • 10 mm is 0.475 mm larger than 3/8 inch.

Nearby inch fractions

Sixteenth-inch steps from the same 1 in = 25.4 mm factor. Linked rows have their own pages. The full fraction table is on inch to mm.

InchesDecimalMillimeters
1/8 in0.1253.175 mm
3/16 in0.18754.7625 mm
1/4 in0.256.35 mm
5/16 in0.31257.9375 mm
3/8 in0.3759.525 mm
7/16 in0.437511.1125 mm
1/2 in0.512.7 mm
9/16 in0.562514.2875 mm
5/8 in0.62515.875 mm

Other inch fractions to mm

FAQ

  • How many mm is 3/8 inch?

    3/8 inch is 9.525 mm exactly. 0.375 × 25.4 = 9.525. That is 0.9525 cm. The decimal form is 0.375 inch.

  • What is 3/8 inch in mm?

    3/8 inch in mm is 9.525 mm. Searches for 3/8 inch to mm use this conversion.

  • Is 10 mm the same as 3/8 inch?

    No. 3/8 inch is 9.525 mm. 10 mm is 0.475 mm larger. 9 mm is 0.525 mm smaller, so 10 mm is the nearer whole millimeter.