01 inch equals 25.4 millimeters.
The conversion from inch to millimeters is done by multiplying the inch value by 25.4, because one inch is exactly 25.4 millimeters according to international agreement. This makes it easy to convert any inch measurement to millimeters by scaling up.
Conversion Tool
Result in mm:
Conversion Formula
The formula to convert inches to millimeters is:
millimeters = inches × 25.4
This formula works because the inch is defined as exactly 25.4 millimeters. Multiplying the inch value by 25.4 gives the equivalent length in millimeters.
For example, to convert 1 inch:
- Take the inch value: 1
- Multiply by 25.4: 1 × 25.4 = 25.4
- Result is 25.4 millimeters
Conversion Example
- Convert 5 inches to millimeters:
- Multiply 5 × 25.4
- 5 × 25.4 = 127
- So, 5 inches equal 127 mm
- Convert 0.5 inches to millimeters:
- Multiply 0.5 × 25.4
- 0.5 × 25.4 = 12.7
- Result is 12.7 mm
- Convert 12.75 inches to millimeters:
- Multiply 12.75 × 25.4
- 12.75 × 25.4 = 323.85
- So 12.75 inches equals 323.85 mm
Conversion Chart
The table below shows inches values from -24.0 to 26.0 and their converted millimeter equivalents. Use it to quickly find the millimeters for these inch values without calculating.
| Inch | 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 |
| 2.0 | 50.8 |
| 4.0 | 101.6 |
| 6.0 | 152.4 |
| 8.0 | 203.2 |
| 10.0 | 254.0 |
| 12.0 | 304.8 |
| 14.0 | 355.6 |
| 16.0 | 406.4 |
| 18.0 | 457.2 |
| 20.0 | 508.0 |
| 22.0 | 558.8 |
| 24.0 | 609.6 |
| 26.0 | 660.4 |
Related Conversion Questions
- How many millimeters are in 1 inch exactly?
- What is the quickest way to convert 1 inch to mm without calculator?
- Why does 1 inch equal 25.4 millimeters?
- Can I convert 1 inch to mm by dividing or multiplying?
- Is 1 inch bigger or smaller than 25 millimeters?
- How to write 1 inch in millimeters for technical drawings?
- What is the difference between 1 inch and 1 mm in size?
Conversion Definitions
Inch: An inch is a unit of length in the imperial and US customary systems. It is defined as exactly 25.4 millimeters. Inches are used mainly in the United States, Canada, and the UK for measuring small lengths, like in construction, manufacturing, and daily measurements.
Millimeter: A millimeter is a metric unit of length equal to one-thousandth of a meter. It is widely used worldwide for precise measurements in science, engineering, and everyday objects. Millimeters provide a fine scale for measuring small distances or thicknesses.
Conversion FAQs
Is 25.4 mm always equal to 1 inch?
Yes, 25.4 millimeters is the exact length of 1 inch based on the international standard adopted in 1959. This fixed value replaced older approximations, ensuring consistency in measurements worldwide, especially in manufacturing and engineering fields.
Can inch to millimeter conversion cause errors?
Errors in conversion mostly happen when rounding decimal points or using approximate values. Using 25.4 exactly avoids this, but if you round intermediate results early, small inaccuracies may appear. Always keep enough decimal places for precision when needed.
Why are inches still used if millimeters are more precise?
Inches remain popular in countries with imperial measurement traditions, partly due to industry standards and legacy equipment. Millimeters are metric and more universally adopted globally, but switching systems can be costly or inconvenient in some places, keeping inches in use.
How to convert fractional inches to millimeters?
Convert the fraction to a decimal first, then multiply by 25.4. For example, 1/2 inch is 0.5; 0.5 × 25.4 = 12.7 mm. This approach works well for all fractional inch values, allowing accurate millimeter equivalents.
I’ve put so much effort writing this blog post to provide value to you. It’ll be very helpful for me, if you consider sharing it on social media or with your friends/family. SHARING IS ♥️
