16 inches equals 406.4 millimeters.
The conversion from inches to millimeters is done by multiplying the number of inches by 25.4, since one inch equals exactly 25.4 millimeters. So, 16 inches times 25.4 gives 406.4 mm.
Conversion Tool
Result in mm:
Conversion Formula
The basic formula to convert inches to millimeters is:
Millimeters = Inches × 25.4
This formula works because there are exactly 25.4 millimeters in one inch, an international standard. To convert any length measured in inches to millimeters, multiply the length by 25.4.
Example: Convert 16 inches to millimeters step-by-step:
- Start with 16 inches.
- Multiply 16 by 25.4: 16 × 25.4
- Calculate the product: 16 × 25.4 = 406.4
- The result is 406.4 millimeters.
Conversion Example
Convert 7.5 inches to millimeters:
- Identify the value in inches: 7.5
- Use the formula: mm = inches × 25.4
- Multiply 7.5 × 25.4 = 190.5
- Therefore, 7.5 inches equals 190.5 mm.
Convert 3 inches to millimeters:
- Value in inches: 3
- Multiply 3 by 25.4: 3 × 25.4 = 76.2
- 3 inches equals 76.2 mm.
Convert 0.25 inches to millimeters:
- Value in inches: 0.25
- Multiply 0.25 × 25.4 = 6.35
- So, 0.25 inches equals 6.35 mm.
Conversion Chart
The chart below shows inches from -9.0 to 41.0 and their equivalent millimeter values. You can read across the row to find the mm value for any inch measurement in this range.
| Inches | Millimeters |
|---|---|
| -9.0 | -228.6 |
| -5.0 | -127.0 |
| 0.0 | 0.0 |
| 5.0 | 127.0 |
| 10.0 | 254.0 |
| 15.0 | 381.0 |
| 16.0 | 406.4 |
| 20.0 | 508.0 |
| 25.0 | 635.0 |
| 30.0 | 762.0 |
| 35.0 | 889.0 |
| 40.0 | 1016.0 |
| 41.0 | 1041.4 |
Related Conversion Questions
- How many millimeters is 16 inches in length?
- What is the exact mm equivalent of 16 inches?
- How do you convert 16 inches to millimeters quickly?
- Is 16 inches equal to 400 mm or more?
- What formula converts 16 inches into millimeters?
- Can I convert 16 inches to mm without a calculator?
- How many mm equals 16 inches for construction measurements?
Conversion Definitions
Inches: An inch is a unit of length used primarily in the United States and United Kingdom. It equals exactly 1/12 of a foot or 2.54 centimeters. Inches are commonly used for measuring small distances or dimensions such as screen sizes, paper, and construction materials.
Millimeters: A millimeter is a metric unit of length equal to one thousandth of a meter. It is widely used across the world for precise measurements in science, engineering, and manufacturing. One millimeter equals 0.03937 inches.
Conversion FAQs
Why is one inch equal to 25.4 millimeters?
One inch was internationally defined as exactly 25.4 millimeters in 1959 by agreement among countries using both metric and imperial systems. This fixed value ensures consistency when converting between these units. Before that, inches varied slightly depending on the country or industry.
Can I convert inches to mm by just multiplying by 25?
Multiplying by 25 gives an approximate result, but not exact. Since one inch equals 25.4 millimeters exactly, using 25 will underestimate the mm value slightly. For precise work, always use 25.4 as the multiplier.
Is the conversion different for fractions of an inch?
No, the conversion process stays the same for fractions. You convert the fractional inch to a decimal value first, then multiply by 25.4. For example, 1/2 inch equals 0.5 inches, so multiply 0.5 × 25.4 to get 12.7 mm.
Do negative inch values convert to negative millimeters?
Yes, negative inch values represent lengths in the opposite direction or below a reference point. When converting, negative inches multiply by 25.4 to give negative millimeters, preserving the sign and meaning.
How accurate is the conversion from inches to millimeters?
The conversion is exact because one inch is defined as 25.4 mm exactly, no approximation. However, the precision depends on how many decimal places you keep. For most uses, rounding to four decimals is more than enough.