0.25 inches is equal to 6.35 mm.
To convert inches to millimeters, multiply the inch value by 25.4 because there are 25.4 millimeters in one inch, so 0.25 inches times 25.4 gives you 6.35 millimeters.
Conversion Tool
Result in mm:
Conversion Formula
The formula to convert inches to millimeters is:
millimeters = inches × 25.4
This works, because 1 inch equals exactly 25.4 millimeters. Multiplying the length in inches by 25.4 converts it to its equivalent length in millimeters.
Example with 0.25 inches:
- Start with 0.25 inches
- Multiply by 25.4: 0.25 × 25.4 = 6.35
- Result is 6.35 millimeters
Conversion Example
- Convert 2 inches to mm:
- Multiply 2 × 25.4 = 50.8 mm
- So, 2 inches equals 50.8 millimeters.
- Convert 5.5 inches to mm:
- Multiply 5.5 × 25.4 = 139.7 mm
- Thus, 5.5 inches is 139.7 millimeters.
- Convert 0.1 inches to mm:
- Multiply 0.1 × 25.4 = 2.54 mm
- Result: 0.1 inches equals 2.54 millimeters.
- Convert 12 inches to mm:
- Multiply 12 × 25.4 = 304.8 mm
- Therefore, 12 inches converts to 304.8 millimeters.
Conversion Chart
The chart below shows various inch values from -24.8 to 25.2 converted to millimeters. To use it, find the inch value you want and read across to see its equivalent in mm. Negative values represent lengths in the opposite direction.
| Inches | Millimeters (mm) |
|---|---|
| -24.8 | -629.92 |
| -20.0 | -508.00 |
| -15.5 | -393.70 |
| -10.1 | -256.54 |
| -5.0 | -127.00 |
| 0.0 | 0.00 |
| 0.25 | 6.35 |
| 1.0 | 25.40 |
| 5.2 | 132.08 |
| 10.0 | 254.00 |
| 15.8 | 401.32 |
| 20.5 | 520.70 |
| 25.2 | 640.08 |
Related Conversion Questions
- How many millimeters are in 0.25 inches exactly?
- What is 0.25 inch in mm with decimal places?
- Is 0.25 inches more or less than 6 mm?
- How do I convert a quarter inch to millimeters?
- What’s the formula to change 0.25 inches into mm?
- How to quickly calculate 0.25 inch to millimeters on a calculator?
- Does 0.25 inch equal 6.35 mm or a different number?
Conversion Definitions
Inches: An inch is a unit of length in the imperial system, defined as exactly 25.4 millimeters. It is commonly used in the United States, Canada, and the United Kingdom for measuring smaller distances or objects, such as screen sizes, paper, and construction materials.
Millimeters (mm): Millimeter is a metric unit of length equal to one thousandth of a meter. It is used worldwide for precise measurements in engineering, manufacturing, and everyday objects. One millimeter is equal to 0.03937 inches.
Conversion FAQs
Why is 1 inch equal to 25.4 millimeters?
The inch was redefined internationally in 1959 by agreement between countries using the imperial system, to be exactly 25.4 millimeters. Before that, the inch varied slightly in length depending on region. This exact value allows consistent conversions between metric and imperial units.
Can fractions of an inch accurately convert to millimeters?
Yes, fractional inches can be converted precisely by multiplying the decimal equivalent of the fraction by 25.4. For example, 1/4 inch is 0.25 inches, which multiplied by 25.4 equals 6.35 mm exactly. Decimal conversions avoid rounding errors common with fractions.
Is the conversion factor 25.4 always the same for all types of measurements?
Yes, when converting linear length measurements, 1 inch always equals 25.4 millimeters. However, for other measurements like area or volume, different conversion factors apply because these units involve squared or cubed dimensions.
Does temperature or environment affect the inch to millimeter conversion?
No, the conversion between inches and millimeters is a fixed mathematical ratio and doesn’t change with temperature or environmental conditions. However, physical materials might expand or contract, but units conversions remain constant.
How precise is the conversion from inches to millimeters?
The conversion is exact at 25.4 mm per inch, allowing high precision. The accuracy depends on how many decimal places you keep when converting. Usually, four decimal places, like 6.3500 mm for 0.25 inches, provides sufficient precision for most tasks.