How to Convert MM to Inches
Converting millimeters to inches is simple with our calculator above. The conversion formula is:
Inches = Millimeters ÷ 25.4
This means that one millimeter is approximately 0.03937 inches. To convert any mm measurement to inches, simply divide the number of millimeters by 25.4. For quick reference, our converter tool above provides instant results with up to four decimal places accuracy.
MM to Inches Conversion Table (1-500 mm)
Comprehensive quick reference table for millimeters to inches conversions. Bookmark this page for easy access.
| Millimeters | Inches | Common Uses |
|---|---|---|
| 1 mm | 0.0394 in | Precision measurements, jewelry |
| 2 mm | 0.0787 in | Small screws, watch parts |
| 3 mm | 0.1181 in | Electronic components |
| 4 mm | 0.1575 in | Small bolts, fasteners |
| 5 mm | 0.1969 in | Standard screws, buttons |
| 6 mm | 0.2362 in | Drill bits, small hardware |
| 7 mm | 0.2756 in | Metric bolts |
| 8 mm | 0.3150 in | Medium fasteners |
| 9 mm | 0.3543 in | Socket sizes |
| 10 mm | 0.3937 in | Standard metric size |
| 12 mm | 0.4724 in | Larger bolts |
| 15 mm | 0.5906 in | Wrench sizes |
| 20 mm | 0.7874 in | Pipe fittings |
| 25 mm | 0.9843 in | Close to 1 inch |
| 30 mm | 1.1811 in | Large hardware |
| 40 mm | 1.5748 in | Mechanical parts |
| 50 mm | 1.9685 in | Construction materials |
| 75 mm | 2.9528 in | Pipe diameters |
| 100 mm | 3.9370 in | Small tubes |
| 150 mm | 5.9055 in | Medium pipes |
| 200 mm | 7.8740 in | Larger pipes |
| 250 mm | 9.8425 in | Industrial components |
| 300 mm | 11.8110 in | Structural elements |
| 400 mm | 15.7480 in | Large scale measurements |
| 500 mm | 19.6850 in | Machinery parts |
50+ Common MM to Inches Conversions
Click on any conversion below for instant results. Includes common measurements from 1-200 mm:
Common Use Cases for MM to Inches Conversion
Understanding millimeters to inches conversion is essential for various everyday applications. Whether you're working in engineering, 3D printing, jewelry making, or DIY projects, our converter helps you get accurate measurements instantly.
⚙️ Engineering & Manufacturing
Convert technical drawings, component sizes, and tolerance specifications. A 50mm bearing is 1.969 inches.
💍 Jewelry & Watches
Precise measurements for ring sizes, watch faces, and gemstone dimensions. 6mm stones are 0.236 inches.
🖨️ 3D Printing & Modeling
Convert STL file dimensions, nozzle sizes, and layer heights. Standard 0.4mm nozzle is 0.016 inches.
🔨 Hardware & Fasteners
Bolt sizes, drill bits, and socket measurements. M6 bolts are 6mm (0.236 inches) diameter.
📐 Woodworking & Construction
Material thickness, cut depths, and joint measurements. 18mm plywood is 0.709 inches thick.
🚗 Automotive & Aerospace
Precision parts, bolt specifications, and clearance measurements. Spark plug gaps, piston sizes.
Frequently Asked Questions About MM to Inches
Find answers to the most common questions about converting millimeters to inches:
One millimeter is approximately 0.03937 inches. This conversion factor is internationally standardized and used universally for converting millimeters to inches.
To convert mm to inches, divide the mm value by 25.4. For example: 50 mm ÷ 25.4 = 1.969 inches. Our calculator above does this automatically for any value you enter.
100 mm equals 3.937 inches. This is a common conversion for measuring small objects and technical specifications.
25 mm is 0.984 inches, which is very close to 1 inch. This conversion is often used in engineering and manufacturing.
The formula is: Inches = Millimeters ÷ 25.4. Simply plug in your mm value and divide by 25.4 to get the equivalent in inches.
12 mm equals 0.472 inches. This is commonly used for small fasteners and electronic components.
6 mm equals 0.236 inches. This is a common size for small screws and drill bits.
150 mm equals 5.906 inches. This is commonly used for medium-length measurements and industrial components.
3 mm equals 0.118 inches. This is slightly larger than 1/8 inch and used for small electronics.
The conversion factor 25.4 is exact and defined by international standards. Our calculator provides results accurate to four decimal places for precise technical work.
200 mm equals 7.874 inches. This large conversion is useful for machinery parts and industrial measurements.