0.5 in equals 12.7 mm.
The conversion from inches (in) to millimeters (mm) involves multiplying the inch value by 25.4, since one inch is exactly 25.4 millimeters. Therefore, half an inch (0.5 in) becomes 0.5 × 25.4 = 12.7 mm.
Conversion Tool
Result in mm:
Conversion Formula
The formula to convert inches to millimeters is:
Millimeters (mm) = Inches (in) × 25.4
This works because by international agreement, 1 inch is exactly 25.4 millimeters. So multiplying the inch value by 25.4 gives its equivalent length in millimeters.
Example calculation for 0.5 in:
- Start with 0.5 inches.
- Multiply 0.5 × 25.4 = 12.7.
- Result is 12.7 mm.
Conversion Example
-
Convert 2 in to mm:
- 2 × 25.4 = 50.8 mm
- Each inch is 25.4 mm, so 2 inches is 50.8 mm.
-
Convert 5.75 in to mm:
- 5.75 × 25.4 = 146.05 mm
- Multiply the inch value by 25.4 for millimeters.
-
Convert 0.125 in to mm:
- 0.125 × 25.4 = 3.175 mm
- Small fractions also multiply the same way.
-
Convert 10 in to mm:
- 10 × 25.4 = 254 mm
- 10 inches equals 254 millimeters.
Conversion Chart
The chart below shows values from -24.5 inches to 25.5 inches converted to millimeters. Negative values represent lengths in the opposite direction. To use the chart, locate the inch value in the first column and find the corresponding mm value beside it.
| Inches (in) | Millimeters (mm) |
|---|---|
| -24.5 | -622.3 |
| -23.5 | -596.9 |
| -22.5 | -571.5 |
| -21.5 | -546.1 |
| -20.5 | -520.7 |
| -19.5 | -495.3 |
| -18.5 | -469.9 |
| -17.5 | -444.5 |
| -16.5 | -419.1 |
| -15.5 | -393.7 |
| -14.5 | -368.3 |
| -13.5 | -342.9 |
| -12.5 | -317.5 |
| -11.5 | -292.1 |
| -10.5 | -266.7 |
| -9.5 | -241.3 |
| -8.5 | -215.9 |
| -7.5 | -190.5 |
| -6.5 | -165.1 |
| -5.5 | -139.7 |
| -4.5 | -114.3 |
| -3.5 | -88.9 |
| -2.5 | -63.5 |
| -1.5 | -38.1 |
| -0.5 | -12.7 |
| 0.5 | 12.7 |
| 1.5 | 38.1 |
| 2.5 | 63.5 |
| 3.5 | 88.9 |
| 4.5 | 114.3 |
| 5.5 | 139.7 |
| 6.5 | 165.1 |
| 7.5 | 190.5 |
| 8.5 | 215.9 |
| 9.5 | 241.3 |
| 10.5 | 266.7 |
| 11.5 | 292.1 |
| 12.5 | 317.5 |
| 13.5 | 342.9 |
| 14.5 | 368.3 |
| 15.5 | 393.7 |
| 16.5 | 419.1 |
| 17.5 | 444.5 |
| 18.5 | 469.9 |
| 19.5 | 495.3 |
| 20.5 | 520.7 |
| 21.5 | 546.1 |
| 22.5 | 571.5 |
| 23.5 | 596.9 |
| 24.5 | 622.3 |
| 25.5 | 647.7 |
Related Conversion Questions
- How many millimeters are in 0.5 inches exactly?
- What is the formula to convert 0.5 in to mm?
- Can I convert 0.5 inches to millimeters using a calculator?
- Is 0.5 inches equal to 12.7 mm?
- How do I convert fractions of an inch like 0.5 to millimeters?
- What tools help convert 0.5 in to mm fast?
- Why does 0.5 inch equal 12.7 mm and not a different number?
Conversion Definitions
in (inch): An inch is a unit of length in the imperial and US customary systems, defined as exactly 25.4 millimeters. It is used commonly in the United States, Canada, and the UK for measuring smaller distances or dimensions in daily life and industry.
mm (millimeter): The millimeter is a metric unit of length, equal to one thousandth of a meter. It is widely used around the world for precise measurements in science, engineering, and manufacturing, representing very small distances with high accuracy.
Conversion FAQs
Why is 1 inch equal to exactly 25.4 millimeters?
The inch was internationally standardized to equal exactly 25.4 millimeters in 1959, through agreements among English-speaking countries. Earlier definitions varied slightly, but this fixed value allows consistent conversions between imperial and metric units.
Can I convert inches to millimeters without a calculator?
You can estimate by multiplying inches by 25.4 mentally or using a simple fraction: 1 inch ≈ 25 mm, so half inch ≈ 12.7 mm. For exact values, a calculator or conversion chart is recommended to avoid errors.
Is the conversion factor always 25.4 for all inch values?
Yes, the conversion factor of 25.4 mm per inch is constant for all measurements. Whether converting 0.1 inch or 100 inches, multiplying by 25.4 gives the correct millimeter equivalent.
What happens if I input negative inches in the conversion tool?
Negative inches represent lengths in the opposite direction or below a reference point. The tool and formula apply the same way, converting negative inch values into negative millimeter values.
Why do some sources show slight variations in inch to mm conversions?
Before the 1959 international agreement, inch was defined differently in countries or industries, causing small variations. Modern measurements use exactly 25.4 mm per inch, ensuring uniformity. Older sources might reflect those earlier definitions.