1/2 inch to mm
Decimal: 0.5 inch
1/2 inch (0.5 inch) = 12.7 mm exactly (1.27 cm). The international inch is 25.4 mm, so multiply the inch value by 25.4.
- Millimeters
- 12.7
- Decimal inches
- 0.5000
- Nearest 1/64
- 1/2 in (exact on 1/64)
- Feet + inches
- 0 ft 0.500 in
The inches fraction result is rounded to the nearest 1/64 fraction.
1/2 inch to mm conversion
1/2 inch (0.5 inch) × 25.4 = 12.7 mm. Reverse: 12.7 ÷ 25.4 = 0.5 in.
1/2 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 1/2 inch to mm
- Write the length as a decimal inch if needed: 1/2 in = 0.5 in (0.5 inch).
- Multiply by 25.4: 0.5 × 25.4 = 12.7 mm.
- Optional centimeters: divide millimeters by 10 → 1.27 cm.
Nearest metric size
The nearest metric size is 13 mm, 0.3 mm larger than 12.7 mm.
A 13 mm wrench, socket, or drill is 0.3 mm larger than 1/2 inch (12.7 mm). A 12 mm tool is 0.7 mm smaller. 13 mm is not the same as 1/2 inch.
1/2 inch is 12.7 mm, not a whole millimeter. Whole-millimeter neighbors:
- 12 mm is 0.7 mm smaller than 1/2 inch.
- 13 mm is 0.3 mm larger than 1/2 inch.
1/16 to 1 inch fraction chart
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.
| Inches | Decimal | Millimeters |
|---|---|---|
| 1/16 in | 0.0625 | 1.5875 mm |
| 1/8 in | 0.125 | 3.175 mm |
| 3/16 in | 0.1875 | 4.7625 mm |
| 1/4 in | 0.25 | 6.35 mm |
| 5/16 in | 0.3125 | 7.9375 mm |
| 3/8 in | 0.375 | 9.525 mm |
| 7/16 in | 0.4375 | 11.1125 mm |
| 1/2 in | 0.5 | 12.7 mm |
| 9/16 in | 0.5625 | 14.2875 mm |
| 5/8 in | 0.625 | 15.875 mm |
| 11/16 in | 0.6875 | 17.4625 mm |
| 3/4 in | 0.75 | 19.05 mm |
| 13/16 in | 0.8125 | 20.6375 mm |
| 7/8 in | 0.875 | 22.225 mm |
| 15/16 in | 0.9375 | 23.8125 mm |
| 1 in | 1 | 25.4 mm |
Other inch fractions to mm
Related conversions
FAQ
How many mm is 1/2 inch?
1/2 inch is 12.7 mm exactly. 1/2 × 25.4 = 12.7. That is 1.27 cm. The decimal form is 0.5 inch. 12 mm is 0.7 mm smaller; 13 mm is 0.3 mm larger.
What is 1/2 inch in mm?
1/2 inch in mm is 12.7 mm. The same length is 1.27 cm. Searches for 1/2 inch to mm and half inch to mm use this conversion.
Is 13 mm the same as 1/2 inch?
No. 1/2 inch is 12.7 mm (0.5 inch). 13 mm is 0.3 mm larger. A 13 mm wrench, socket, or drill is close, not the same size.
Is 1/2 inch 12 mm or 13 mm?
Neither is exact. 1/2 inch is 12.7 mm. 12 mm is 0.7 mm short of 1/2 in; 13 mm is 0.3 mm long. Use 12.7 mm when the drawing is in millimeters.