8 mm to Inches
Convert 8 millimeters to inches — instant, accurate, and easy
The Answer
How to Convert 8 mm to Inches
To convert 8 millimeters to inches, divide the millimeter value by 25.4. This is because one inch equals exactly 25.4 millimeters — a standard defined by international agreement.
The Calculation
Applying the formula to 8 mm:
Result Summary for 8 mm
- Decimal inches: 0.3150″
- Fractional inches: 5/16″ (nearest 1/64)
- Feet and inches: 0 ft 0.31 in
Common Uses for 8mm Measurements
A measurement of 8 millimeters is frequently used in hardware, small tool sizing, jewelry, watchmaking, and various manufacturing contexts.
You might encounter 8mm in items like standard screw diameters, drill bits, small mechanical parts, and detailed craft measurements.
Why Convert 8 mm to Inches?
Converting 8mm to inches is essential when working with hardware, tools, materials, or products from countries that use different measurement systems.
Knowing that 8 mm equals 0.3150 inches helps you make accurate measurements and avoid costly mistakes.
Reference Table — Values Near 8 mm
| Millimeters | Decimal Inches | Fractional Inches |
|---|---|---|
| 5 mm | 0.1969″ | 13/64″ |
| 6 mm | 0.2362″ | 15/64″ |
| 7 mm | 0.2756″ | 9/32″ |
| 8 mm | 0.3150″ | 5/16″ |
| 9 mm | 0.3543″ | 23/64″ |
| 10 mm | 0.3937″ | 25/64″ |
| 11 mm | 0.4331″ | 7/16″ |
8 mm in Other Units
Millimetres convert cleanly into every other length unit. Here is 8 mm expressed seven different ways — useful when a drawing, spec sheet or supplier quotes a unit other than inches.
| Unit | 8 mm equals |
|---|---|
| Centimetres (cm) | 0.8 cm |
| Metres (m) | 0.008 m |
| Inches (in) | 0.3150 in |
| Feet (ft) | 0.0262 ft |
| Yards (yd) | 0.00875 yd |
| Thousandths of an inch (mil) | 315 mil |
| Typographic points (1/72 in) | 22.68 pt |
How Accurate Is Each Fraction of 8 mm?
8 mm is exactly 0.3150″. Any fraction is a rounding of that number, so each one carries a small error. This table shows the closest fraction at each common denominator and how far it actually sits from 8 mm.
| Rounded to | Fraction | Decimal | Difference |
|---|---|---|---|
| Nearest 1/2″ | 1/2″ | 0.5000″ | +4.700 mm |
| Nearest 1/4″ | 1/4″ | 0.2500″ | −1.650 mm |
| Nearest 1/8″ | 3/8″ | 0.3750″ | +1.525 mm |
| Nearest 1/16″ | 5/16″ | 0.3125″ | −0.062 mm |
| Nearest 1/32″ | 5/16″ | 0.3125″ | −0.062 mm |
| Nearest 1/64″ | 5/16″ | 0.3125″ | −0.062 mm |
For woodworking, DIY and general workshop use, 5/16″ is the practical choice — it lands within 0.4 mm of 8 mm, which is finer than most tape measures resolve. For machining, toolmaking or CAD, use the decimal value 0.3150″ rather than any fraction.
FAQ About 8 mm to Inches
How many inches is 8 mm?
8 millimeters equals 0.3150 inches, or approximately 5/16″ (nearest 1/64 inch).
How accurate is the 8 mm to inches conversion?
The conversion of 8 mm to 0.3150 inches is mathematically precise, based on 1 inch = 25.4 millimeters exactly.
Can I convert 8 mm to feet?
Yes. 8 millimeters equals approximately 0 ft 0.31 in.