Elara Bennett01 inch equals 25.4 millimeters (mm).
An inch is a unit of length in the imperial system, and millimeter is a metric unit. To convert inches to millimeters, multiply the number of inches by 25.4, since one inch exactly equals 25.4 millimeters.
Conversion Tool
Result in mm:
Conversion Formula
The formula to convert inches to millimeters is:
millimeters = inches × 25.4
This works because by international agreement, 1 inch is exactly equal to 25.4 millimeters. The conversion factor 25.4 comes from the definition of the inch in metric terms.
For example, converting 1 inch:
- Take the value in inches: 1
- Multiply by 25.4: 1 × 25.4 = 25.4
- The result is 25.4 millimeters
Conversion Example
- Convert 3 inches to mm:
- 3 × 25.4 = 76.2 mm
- So 3 inches equals 76.2 millimeters
- Convert 0.5 inch to mm:
- 0.5 × 25.4 = 12.7 mm
- Half an inch is 12.7 millimeters
- Convert 7.25 inches to mm:
- 7.25 × 25.4 = 184.15 mm
- Therefore, 7.25 inches equals 184.15 mm
- Convert 10 inches to mm:
- 10 × 25.4 = 254 mm
- Ten inches is 254 millimeters
Conversion Chart
The chart below shows inch values from -24.0 to 26.0 and their equivalent in millimeters. Negative values represent measurements in the opposite direction from a reference point.
| Inches | Millimeters (mm) |
|---|---|
| -24.0 | -609.6 |
| -20.0 | -508.0 |
| -16.0 | -406.4 |
| -12.0 | -304.8 |
| -8.0 | -203.2 |
| -4.0 | -101.6 |
| 0.0 | 0.0 |
| 4.0 | 101.6 |
| 8.0 | 203.2 |
| 12.0 | 304.8 |
| 16.0 | 406.4 |
| 20.0 | 508.0 |
| 24.0 | 609.6 |
| 26.0 | 660.4 |
Related Conversion Questions
- How many millimeters are in 1 inch exactly?
- What is the formula to change 1 inch into millimeters?
- Can I convert 1 inch to mm without a calculator?
- Why does 1 inch equal 25.4 mm and not another number?
- How to convert 1 inch to mm for engineering drawings?
- Is 1 inch always 25.4 millimeters in every country?
- What is 1 inch in millimeters rounded to two decimals?
Conversion Definitions
Inch: An inch is a unit of length that belongs to the imperial and US customary measurement systems. It is traditionally divided into smaller parts like halves, quarters, and sixteenths. One inch is defined exactly as 25.4 millimeters internationally.
Millimeter (mm): The millimeter is a metric unit of length equal to one thousandth of a meter. It is commonly used for small measurements in science, engineering, and everyday objects. Millimeters provide precise dimensions in metric measurements.
Conversion FAQs
Can the inch to millimeter conversion change over time?
No, the inch is fixed by international agreement to exactly 25.4 millimeters since 1959. There is no change in the conversion factor, ensuring consistency worldwide.
How accurate is converting 1 inch to 25.4 mm?
It is perfectly accurate because the inch is defined to be exactly 25.4 mm. Any difference occurs only due to rounding in practical measurements, but the conversion itself is exact.
Why are both inch and millimeter used if metric is widespread?
Inch remains popular in the US and few other countries for manufacturing, construction, and design. Millimeters are used globally in science and most metric countries. Both units coexist due to historical and practical reasons.
How do I convert fractional inches to millimeters?
Convert the fraction to a decimal first (for example, ½ inch is 0.5 inches), then multiply by 25.4. This gives you the millimeter value for fractions.
Can negative inches be converted to millimeters?
Yes, negative inches represent lengths or positions in the opposite direction, and multiplying by 25.4 converts negative inches directly to negative millimeters.
