1.5 inches is equal to 38.1 millimeters.
The conversion from inches to millimeters is done by multiplying the inch value by 25.4, since one inch equals exactly 25.4 millimeters. Therefore, 1.5 inches times 25.4 gives the result in millimeters.
Conversion Tool
Result in millimeters:
Conversion Formula
The formula to convert inches to millimeters is:
millimeters = inches × 25.4
This works because by international agreement, one inch is exactly 25.4 millimeters. So to convert any length in inches to millimeters, multiply the inches value by 25.4. For example:
- Convert 1.5 inches: 1.5 × 25.4 = 38.1 millimeters
- Convert 2 inches: 2 × 25.4 = 50.8 millimeters
Multiplying by 25.4 scales the inch measurement to the metric millimeter scale, which is smaller and more precise.
Conversion Example
- Convert 3.2 inches to millimeters:
- Multiply 3.2 by 25.4 to get millimeters.
- 3.2 × 25.4 = 81.28 millimeters.
- Thus, 3.2 inches equals 81.28 millimeters.
- Convert 0.75 inches:
- 0.75 × 25.4 = 19.05 millimeters.
- Therefore, 0.75 inches is 19.05 millimeters.
- Convert 5 inches:
- 5 × 25.4 = 127 millimeters.
- 5 inches correspond to 127 millimeters.
- Convert 10.5 inches:
- 10.5 × 25.4 = 266.7 millimeters.
- So 10.5 inches equals 266.7 millimeters.
Conversion Chart
Below is the chart showing inches from -23.5 to 26.5 with their converted millimeter values. You can find the millimeter length by locating the inch value in the first column and reading across to the millimeter column.
| Inches | Millimeters |
|---|---|
| -23.5 | -596.9 |
| -20.0 | -508.0 |
| -15.0 | -381.0 |
| -10.0 | -254.0 |
| -5.0 | -127.0 |
| 0.0 | 0.0 |
| 5.0 | 127.0 |
| 10.0 | 254.0 |
| 15.0 | 381.0 |
| 20.0 | 508.0 |
| 23.5 | 596.9 |
| 26.5 | 673.1 |
Related Conversion Questions
- How many millimeters are in 1.5 inches exactly?
- What is the formula to convert 1.5 inches to millimeters?
- Is 1.5 inches larger than 38 millimeters?
- How to convert 1.5 inches into millimeters without a calculator?
- How precise is the conversion of 1.5 inches to millimeters?
- Why does 1.5 inches equal 38.1 millimeters?
- Can I use 25.4 as a multiplier for 1.5 inches to find millimeters?
Conversion Definitions
Inches: An inch is a unit of length in the imperial and United States customary systems. It is equal to 1/12 of a foot or 1/36 of a yard. One inch is exactly 25.4 millimeters by international agreement, used mainly in the US, UK, and Canada for measuring small distances or sizes.
Millimeters: A millimeter is a metric unit of length equal to one thousandth of a meter (0.001 meters). It is commonly used worldwide for measuring small lengths or thicknesses with high precision. Millimeters are part of the International System of Units (SI).
Conversion FAQs
Why is one inch equal to exactly 25.4 millimeters?
This exact value was agreed upon internationally in 1959 by countries including the US, UK, and Canada. Prior to this, inches varied slightly between regions. Setting 1 inch = 25.4 mm standardizes measurements across systems, allowing seamless conversion between imperial and metric units.
Can I convert inches to millimeters without a calculator?
Yes, by memorizing the fact that 1 inch equals 25.4 millimeters, you can multiply the inch value by 25.4 manually. For rough estimates, multiply by 25 or 26 to get close. For precise work, a calculator or conversion chart helps avoid small errors.
Can inches be a decimal when converting to millimeters?
Absolutely, inches can be expressed in decimals or fractions. When converting to millimeters, decimals are easier to calculate. For example, 1.5 inches converts directly by multiplying 1.5 × 25.4, yielding an exact millimeter value.
Does the conversion formula change for negative inch values?
No, the formula stays the same. Negative inch values represent lengths in the opposite direction or below a reference point. Multiply the negative inch by 25.4 to get the corresponding negative millimeter value, maintaining the sign.
Is the conversion factor always 25.4 or does it vary?
The conversion factor 25.4 mm per inch is fixed and internationally recognized. It does not change regardless of context, measurement type, or location. This consistency ensures uniform results converting inches to millimeters worldwide.