Practical measurement guide
3/8 Inch to MM and CM
Convert 3/8 inch to decimal inches, centimeters, and millimeters with ruler-position and rounding guidance.
3/8 inch equals 0.375 decimal inches, 0.9525 cm, and 9.525 mm.
in
Decimals and fractions work, for example 1.5, 1/2, or 1 1/2.
mm
Try a value
Fractions
0.375 in = 9.525 mm
0.375 in × 25.4 = 9.525 mm
Decimal inches0.375 in
Feet + inches0 ft 0.375 in
Nearest 1/16 inch3/8"
Fraction inch result
3/8 inch equals 0.375 inches, 0.9525 cm, and 9.525 mm.
Calculation method
First divide 3 by 8 to get decimal inches. Then multiply decimal inches by 25.4 for millimeters or by 2.54 for centimeters.
Nearby ruler fractions
| Fraction | Decimal inches | Millimeters |
|---|---|---|
| 2/8 in | 0.25 | 6.35 mm |
| 3/8 in | 0.375 | 9.525 mm |
| 4/8 in | 0.5 | 12.7 mm |
Precision note
This page keeps the fraction exact and rounds the metric result only for display. Use 64ths when the tool or ruler supports fine increments; otherwise round to 32nds, 16ths, or 8ths.
Related measurement tools
Frequently asked questions
What is 3/8 inch as a decimal?
3/8 inch is 0.375 decimal inches.
How many mm is 3/8 inch?
3/8 inch equals 9.525 millimeters.
Is the fraction simplified?
Yes. This page uses a canonical common ruler fraction and does not publish duplicate simplified equivalents.