01 inch equals 25.4 millimeters (mm).
The inch is a unit of length in the imperial system, and millimeters are part of the metric system. To convert inches to millimeters, multiply the inch value by 25.4 because one inch equals exactly 25.4 millimeters.
Conversion Tool
Result in mm:
Conversion Formula
To convert inches to millimeters, multiply the number of inches by 25.4. The formula is:
Millimeters (mm) = Inches (in) × 25.4
This works because one inch is defined as exactly 25.4 millimeters internationally. So, if you have a length in inches, multiplying it convert it to millimeters gives the equivalent length in the metric system.
Example: Convert 1 inch to millimeters
- Start with 1 inch.
- Multiply 1 × 25.4 = 25.4
- Therefore, 1 inch equals 25.4 millimeters.
Conversion Example
- Convert 3 inches to mm:
- Multiply 3 × 25.4 = 76.2 mm
- So, 3 inches equals 76.2 millimeters.
- Convert 0.5 inches to mm:
- Multiply 0.5 × 25.4 = 12.7 mm
- 0.5 inches is 12.7 millimeters.
- Convert 10 inches to mm:
- Multiply 10 × 25.4 = 254 mm
- 10 inches equals 254 millimeters.
- Convert 7.25 inches to mm:
- Multiply 7.25 × 25.4 = 184.15 mm
- 7.25 inches converts to 184.15 millimeters.
- Convert 0.125 inches to mm:
- Multiply 0.125 × 25.4 = 3.175 mm
- 0.125 inches equals 3.175 millimeters.
Conversion Chart
| Inches | Millimeters (mm) |
|---|---|
| -24.0 | -609.6 |
| -20.0 | -508.0 |
| -15.0 | -381.0 |
| -10.0 | -254.0 |
| -5.0 | -127.0 |
| 0.0 | 0.0 |
| 5.0 | 127.0 |
| 10.0 | 254.0 |
| 15.0 | 381.0 |
| 20.0 | 508.0 |
| 26.0 | 660.4 |
This chart helps you quickly find the millimeter equivalent for inches from -24.0 to 26.0. To use it, find the inch value in the left column and read across for the corresponding millimeters on the right.
Related Conversion Questions
- How many millimeters are in exactly 1 inch?
- What is the formula to convert 1 inch to mm?
- Is 1 inch larger or smaller than 25 mm?
- How do I convert 1 inch to millimeters without a calculator?
- Can you show me the step-by-step for converting 1 inch to mm?
- What is the equivalent of 1 inch in millimeters in metric units?
- Why is 1 inch equal to 25.4 mm?
Conversion Definitions
Inch: An inch is a length measurement unit in the imperial and United States customary systems. It equals exactly 1⁄12 of a foot or 2.54 centimeters. Inches are used mainly in the US for measuring small distances, screen sizes, and construction materials.
Millimeter (mm): A millimeter is a metric unit of length equal to one-thousandth of a meter. It is commonly used worldwide for precise measurements in science, engineering, and everyday objects. There are 1000 millimeters in one meter.
Conversion FAQs
Why is one inch exactly 25.4 millimeters?
The inch was standardized internationally in 1959 through an agreement between English-speaking countries. It fixed the length of one inch to exactly 25.4 millimeters to ensure consistency across measurement systems. This replaced older, varying definitions of the inch.
Can I convert inches to millimeters by just multiplying by 25?
Multiplying by 25 gives a close approximation but is not exact. One inch equals exactly 25.4 millimeters. So, for accurate conversions, especially in engineering or science, always use 25.4 instead of 25.
Is the conversion factor 25.4 always the same regardless of context?
Yes, the factor 25.4 mm per inch is fixed by international agreement and does not change regardless of context. This ensures conversions between imperial and metric are consistent worldwide.
How can I convert fractional inches to millimeters?
To convert fractional inches, first convert the fraction to a decimal. For example, 1/2 inch is 0.5 inch. Then multiply by 25.4 to get millimeters. This works for any fractional values.
Are inches and millimeters used in different countries?
Yes, inches are mostly used in the United States and a few other countries, while millimeters are part of the metric system used almost everywhere else. Many industries use both depending on standards and regional preferences.