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1.5 inches is equal to 38.1 millimeters.
The conversion from inches to millimeters involves multiplying the inch value by 25.4, since one inch equals exactly 25.4 millimeters. So, 1.5 inches times 25.4 gives the result in millimeters.
Conversion Tool
Result in mm:
Conversion Formula
The formula to convert inches (in) to millimeters (mm) is:
mm = in × 25.4
This works because one inch is exactly 25.4 millimeters by international agreement. Multiplying any length in inches by 25.4 converts it into millimeters.
For example, to convert 1.5 in to mm:
- Take the inch value: 1.5
- Multiply by 25.4: 1.5 × 25.4 = 38.1
- The result is 38.1 mm
Conversion Example
- Example 1: Convert 3 in to mm
- Start with 3 inches
- Multiply 3 × 25.4 = 76.2
- Result: 3 in = 76.2 mm
- Example 2: Convert 0.75 in to mm
- Begin with 0.75 inches
- Multiply 0.75 × 25.4 = 19.05
- Result: 0.75 in equals 19.05 mm
- Example 3: Convert 5.2 in to mm
- Take 5.2 inches
- Multiply 5.2 × 25.4 = 132.08
- Result: 5.2 in = 132.08 mm
- Example 4: Convert 10 in to mm
- Start from 10 inches
- Multiply 10 × 25.4 = 254
- Result: 10 in equals 254 mm
Conversion Chart
This chart shows values from -23.5 inches to 26.5 inches converted into millimeters. You can look up any inch value in the left column to find its equivalent in millimeters in the right column.
| Inches (in) | Millimeters (mm) |
|---|---|
| -23.5 | -23.5 × 25.4 = -596.9 |
| -20 | -20 × 25.4 = -508 |
| -15 | -15 × 25.4 = -381 |
| -10 | -10 × 25.4 = -254 |
| -5 | -5 × 25.4 = -127 |
| 0 | 0 × 25.4 = 0 |
| 5 | 5 × 25.4 = 127 |
| 10 | 10 × 25.4 = 254 |
| 15 | 15 × 25.4 = 381 |
| 20 | 20 × 25.4 = 508 |
| 23.5 | 23.5 × 25.4 = 596.9 |
| 26.5 | 26.5 × 25.4 = 673.1 |
Related Conversion Questions
- How many millimeters are in 1.5 inches exactly?
- What is the step-by-step method to convert 1.5 in to mm?
- Is 1.5 inches equal to 38 millimeters or 38.1 mm?
- Can I use 25.4 as the conversion factor for 1.5 inches to mm?
- How do I convert 1.5 in to mm using a calculator?
- Why does 1.5 inches equal 38.1 millimeters?
- Are there any shortcuts for converting 1.5 inches into millimeters?
Conversion Definitions
in: The inch (in) is a unit of length used in the imperial and US customary systems. It equals exactly 2.54 centimeters or 25.4 millimeters. Inches are used for measuring small distances, commonly in construction, engineering, and manufacturing.
mm: The millimeter (mm) is a metric unit of length equal to one-thousandth of a meter. It is widely used worldwide for precise measurements in engineering, machining, and sciences, representing small distances with high accuracy.
Conversion FAQs
Why is 25.4 used as the exact conversion factor from inches to millimeters?
The number 25.4 millimeters per inch is internationally agreed through standards organizations to provide a precise and unchanging conversion. It was established to unify measurement systems, ensuring consistent and exact length conversions between imperial and metric units.
Can I convert fractional inches like 1 1/2 inches directly into millimeters?
Yes, fractions must first be converted into decimal form before multiplying by 25.4. For example, 1 1/2 inches equals 1.5 inches in decimal; multiply 1.5 by 25.4 to get 38.1 millimeters.
Is the conversion result always exact or rounded?
Since 25.4 is exact, the conversion result is mathematically precise. However, decimal results may be rounded for display or practical use, depending on required precision.
Can negative values in inches be converted to millimeters?
Yes, negative inch values represent lengths in the opposite direction, and they convert to negative millimeter values by multiplying the negative inch value by 25.4.
Are there any tools besides manual calculation to convert inches to millimeters?
Many online converters, calculators, and software tools exist to perform this conversion automatically, including the simple JavaScript tool above, which converts entered inch values to millimeters instantly.