0.25 inch equals 6.35 millimeters.
To convert 0.25 inch to millimeters, you multiply the inch value by 25.4 because one inch is exactly 25.4 millimeters. Therefore, 0.25 inch times 25.4 equals 6.35 mm.
Conversion Tool
Result in mm:
Conversion Formula
The formula to convert inches to millimeters is: millimeters = inches × 25.4. This formula works because one inch is defined as exactly 25.4 millimeters by international agreement. The factor 25.4 is a fixed constant that relates the two units.
Example calculation:
- Given 0.25 inch, multiply by 25.4:
- 0.25 × 25.4 = 6.35 mm
This multiplication converts the length from inch unit to the metric millimeter unit.
Conversion Example
- Convert 1.5 inches to mm:
- Multiply 1.5 by 25.4.
- 1.5 × 25.4 = 38.1 mm.
- Therefore, 1.5 inches equals 38.1 mm.
- Convert 0.75 inch to mm:
- Multiply 0.75 × 25.4.
- 0.75 × 25.4 = 19.05 mm.
- This means 0.75 inch equals 19.05 mm.
- Convert 2 inches to mm:
- Multiply 2 × 25.4.
- 2 × 25.4 = 50.8 mm.
- So, 2 inches is 50.8 mm.
- Convert 0.1 inch to mm:
- Multiply 0.1 by 25.4.
- 0.1 × 25.4 = 2.54 mm.
- Therefore, 0.1 inch equals 2.54 mm.
Conversion Chart
The table below shows inch values from -24.8 to 25.2 and their millimeter equivalents. You can read across to find the mm value for an inch measurement near those numbers. Negative values show lengths in the opposite direction or below zero.
| Inch | Millimeter (mm) |
|---|---|
| -24.8 | -629.92 |
| -20.0 | -508.00 |
| -15.5 | -393.70 |
| -10.2 | -259.08 |
| -5.0 | -127.00 |
| -1.0 | -25.40 |
| 0 | 0.00 |
| 1.0 | 25.40 |
| 5.0 | 127.00 |
| 10.0 | 254.00 |
| 15.0 | 381.00 |
| 20.0 | 508.00 |
| 24.8 | 629.92 |
| 25.2 | 640.08 |
Related Conversion Questions
- How many millimeters are in 0.25 inch exactly?
- What is the easiest way convert 0.25 inch to mm?
- Is 0.25 inch bigger or smaller than 6 mm?
- Can I use 0.25 inch to mm conversion for engineering measurements?
- How to convert 0.25 inch to millimeters without a calculator?
- What is 0.25 inch in millimeters rounded to two decimals?
- Does 0.25 inch equal 6.35 mm or 6.5 mm?
Conversion Definitions
Inch: An inch is a unit of length in the imperial and US customary systems, equal to 1/12 of a foot and exactly 25.4 millimeters. It often used for measuring smaller lengths like screen sizes, paper dimensions, or construction materials.
Millimeter (mm): A millimeter is a metric unit of length equal to one thousandth of a meter. It is widely used for precise measurements in science, engineering, and everyday tasks where small lengths are needed.
Conversion FAQs
Can I convert fractional inches like 0.25 using the same formula?
Yes, fractional inches such as 0.25 are converted by multiplying by 25.4. Because 25.4 mm equals 1 inch, multiplying any decimal or fraction of an inch by 25.4 gives the exact length in millimeters.
Why is 25.4 the number used to convert inches to millimeters?
The number 25.4 comes from the international agreement that defines one inch as exactly 25.4 millimeters. This standard ensures consistent conversions worldwide, replacing older approximations.
Is the conversion precise for engineering applications?
The conversion using 25.4 is exact and accepted for engineering. However, rounding after conversion might cause small inaccuracies. Using more decimal places reduces errors in sensitive measurements.
What happens when converting negative inch values to millimeters?
Negative inch values convert to negative millimeters, representing direction or positions below a zero reference. The same formula applies: multiply by 25.4, keeping the negative sign.
Does the conversion change if the inch value is very large or small?
The conversion formula holds for any size of inch value, large or small. Because it is a linear relation, multiplying by 25.4 will scale the value consistently regardless of magnitude.