42 inches is equal to 1066.8 millimeters.
To convert inches to millimeters, multiply the length value by 25.4 because one inch equals 25.4 millimeters. So, 42 inches times 25.4 gives 1066.8 millimeters.
Conversion Tool
Result in mm:
Conversion Formula
The formula to convert inches to millimeters is simple: multiply the number of inches by 25.4. This works because one inch equals exactly 25.4 millimeters, a value established by international agreement.
Mathematically, it looks like this:
millimeters = inches × 25.4
For example, converting 42 inches:
- Start with 42 inches.
- Multiply 42 × 25.4 = 1066.8 millimeters.
- The result is 1066.8 mm.
Conversion Example
- Convert 10 inch to mm:
- Multiply 10 × 25.4 = 254 mm.
- The length is 254 millimeters.
- Convert 25.5 inch to mm:
- Calculate 25.5 × 25.4 = 647.7 mm.
- So, 25.5 inches equals 647.7 millimeters.
- Convert 50 inch to mm:
- Multiply 50 × 25.4 = 1270 mm.
- This means 50 inches is 1270 millimeters.
- Convert 33.3 inch to mm:
- 33.3 × 25.4 = 845.82 mm.
- Therefore, 33.3 inches equals 845.82 mm.
Conversion Chart
The following table shows inches from 17.0 to 67.0, converted to millimeters. You can find a value in inches, then look directly across to see its equivalent in millimeters.
| Inches | Millimeters (mm) |
|---|---|
| 17.0 | 431.8 |
| 22.0 | 558.8 |
| 27.0 | 685.8 |
| 32.0 | 812.8 |
| 37.0 | 939.8 |
| 42.0 | 1066.8 |
| 47.0 | 1193.8 |
| 52.0 | 1320.8 |
| 57.0 | 1447.8 |
| 62.0 | 1574.8 |
| 67.0 | 1701.8 |
Related Conversion Questions
- How many millimeters are in 42 inches exactly?
- What is 42 inch converted to millimeters with decimal precision?
- Can I convert 42 inches into mm without using a calculator?
- How does 42 inches compare to millimeters in length?
- Is 42 inch longer than 1000 mm?
- What formula should I use to convert 42 inches to mm?
- How to convert 42 inch to mm step by step?
Conversion Definitions
Inch: An inch is a unit of length in the imperial and US customary measurement systems. It equals exactly 1/12 of a foot or 2.54 centimeters. Historically, the inch was based on the width of a thumb, but now it is precisely defined by international agreement as 25.4 millimeters.
Millimeter (mm): The millimeter is a metric unit of length, equal to one thousandth of a meter. It is used for precise measurements in engineering, manufacturing, and everyday applications. Because it is small, millimeters are ideal for describing dimensions of small objects or detailed measurements.
Conversion FAQs
Why is the inch defined as 25.4 millimeters?
The inch was standardized to 25.4 millimeters in 1959 by an international agreement between countries using the imperial and metric systems. This fixed value allows consistent and accurate conversions between the two systems, avoiding confusion from previous slightly different definitions.
Can I convert inches to millimeters without a calculator?
You can estimate by remembering that one inch equals about 25 millimeters plus a bit more. Multiplying by 25.4 exactly requires a calculator or conversion table for precision, but rough conversions can be done mentally for quick approximations.
Is the conversion factor always 25.4?
Yes, the conversion factor is exactly 25.4 millimeters per inch. This value is fixed and does not change regardless of the measurement context, ensuring consistency worldwide.
How precise is the conversion from inch to millimeter?
Since 1 inch equals exactly 25.4 millimeters, the conversion is precise without any rounding errors in the factor itself. However, measurement tools and input values can affect overall precision in practice.
Are there any common mistakes when converting inches to millimeters?
Common mistakes include using an approximate conversion factor like 25 instead of 25.4, which leads to inaccurate results. Also, forgetting to multiply or mixing up units may cause errors, so careful calculation is advised.