Use this inches to millimeters converter to quickly convert any measurement from inches (in) to millimeters (mm). Enter the number of inches into the calculator below to get an accurate result instantly.
Convert Inches to Millimeters
Enter a value in inches to instantly calculate the equivalent value in millimeters.
Formula: millimeters = inches × 25.4
How to Convert Inches to Millimeters
To convert inches to millimeters, multiply the number of inches by 25.4. One inch is exactly equal to 25.4 millimeters.
Inches to Millimeters Formula
Millimeters = Inches × 25.4
For example, to convert 5 inches to millimeters:
5 × 25.4 = 127 millimeters
Therefore, 5 inches equals 127 millimeters.
This inches to millimeters converter formula provides an exact result because one inch is defined as exactly 25.4 millimeters.
Inches to Millimeters Converter Table
| Inches | Millimeters |
|---|---|
| 0.25 in | 6.35 mm |
| 0.5 in | 12.7 mm |
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 8 in | 203.2 mm |
| 10 in | 254 mm |
Common Inches to Millimeters Conversions
Here are several common inches-to-millimeters conversions for quick reference. Because one inch equals exactly 25.4 millimeters, each value in inches is multiplied by 25.4.
- 0.25 inches = 6.35 millimeters
- 0.5 inches = 12.7 millimeters
- 1 inch = 25.4 millimeters
- 2 inches = 50.8 millimeters
- 3 inches = 76.2 millimeters
- 4 inches = 101.6 millimeters
- 5 inches = 127 millimeters
- 6 inches = 152.4 millimeters
- 8 inches = 203.2 millimeters
- 10 inches = 254 millimeters
- 12 inches = 304.8 millimeters
- 24 inches = 609.6 millimeters
- 36 inches = 914.4 millimeters
Frequently Asked Questions
How many millimeters are in one inch?
There are exactly 25.4 millimeters in one inch.
How do you convert inches to millimeters?
Multiply the measurement in inches by 25.4. For example, 8 inches multiplied by 25.4 equals 203.2 millimeters.
How many millimeters are in half an inch?
Half an inch equals 12.7 millimeters.
How many millimeters are in 12 inches?
Twelve inches equals 304.8 millimeters.
Is 25 millimeters equal to one inch?
Not exactly. One inch equals 25.4 millimeters, so 25 millimeters is slightly less than one inch.
When You Might Need to Convert Inches to Millimeters
Converting inches to millimeters is useful when working with measurements from both the U.S. customary and metric systems. You may need this conversion when reading product dimensions, selecting tools or hardware, completing construction and home-improvement projects, comparing screen sizes, or working with engineering and manufacturing specifications.
Because millimeters provide smaller and more precise measurements, converting inches to millimeters is especially helpful when accuracy matters. For example, a measurement of 2.5 inches converts to exactly 63.5 millimeters.
What Is an Inch?
An inch is a unit of length used primarily in the United States customary and British imperial measurement systems. The abbreviation for inch is in, and inches may also be represented by the double-prime symbol (″).
There are 12 inches in one foot and 36 inches in one yard. Inches are commonly used to measure height, screen sizes, furniture, construction materials, tools and other everyday objects.
What Is a Millimeter?
A millimeter is a metric unit of length equal to one-thousandth of a meter. Its official abbreviation is mm.
Millimeters are commonly used for small, precise measurements in manufacturing, engineering, construction, medicine and product design. There are 10 millimeters in one centimeter and 1,000 millimeters in one meter.
For additional information about metric measurement and SI units, visit the U.S. National Institute of Standards and Technology (NIST).
Understanding the difference between these measurement systems is especially useful when comparing products or specifications from different countries. Inches are commonly used for measurements in the United States, while millimeters are widely used throughout the metric system. Whether you are measuring an object, checking product dimensions, planning a project, selecting hardware, or comparing international sizes, an accurate inches-to-millimeters conversion helps ensure that you are working with the correct measurement.
This inches to millimeters converter is useful when comparing product dimensions, choosing tools or hardware, reviewing construction plans, and working with international measurements.
For fast and accurate results, use our inches to millimeters converter whenever you need to compare measurements between the two units.
Convert Millimeters to Inches
Need to reverse the conversion? Use our millimeters to inches converter to quickly convert measurements from millimeters (mm) to inches (in). One millimeter equals approximately 0.0393701 inches.
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