Clearance Hole Size Chart for Bolts and Screws (Metric)
Metric clearance hole size chart for bolts and screws, including close fit, medium fit, and free fit hole diameters in millimeters
Clearance Hole Size (Metric) Chart
| Nominal Thread Diameter (mm) | Clearance Hole Sizes (mm) | ||
|---|---|---|---|
| Close Fit | Medium Fit | Free Fit | |
| 1.6 | 1.7 | 1.8 | 2.0 |
| 2.0 | 2.2 | 2.4 | 2.6 |
| 2.5 | 2.7 | 2.9 | 3.1 |
| 3.0 | 3.2 | 3.4 | 3.6 |
| 4.0 | 4.3 | 4.5 | 4.8 |
| 5.0 | 5.3 | 5.5 | 5.8 |
| 6.0 | 6.4 | 6.6 | 7.0 |
| 7.0 | 7.4 | 7.6 | 8.0 |
| 8.0 | 8.4 | 9.0 | 10.0 |
| 10.0 | 10.5 | 11.0 | 12.0 |
| 12.0 | 13.0 | 14.0 | 15.0 |
| 14.0 | 15.0 | 16.0 | 17.0 |
| 16.0 | 17.0 | 18.0 | 19.0 |
| 18.0 | 19.0 | 20.0 | 21.0 |
| 20.0 | 21.0 | 22.0 | 24.0 |
| 22.0 | 23.0 | 24.0 | 26.0 |
| 24.0 | 25.0 | 26.0 | 28.0 |
| 27.0 | 28.0 | 30.0 | 32.0 |
| 30.0 | 31.0 | 33.0 | 35.0 |
| 33.0 | 34.0 | 36.0 | 38.0 |
| 36.0 | 37.0 | 39.0 | 42.0 |
| 39.0 | 40.0 | 42.0 | 45.0 |
| 42.0 | 43.0 | 45.0 | 48.0 |
| 45.0 | 46.0 | 48.0 | 52.0 |
| 48.0 | 50.0 | 52.0 | 56.0 |
| 52.0 | 54.0 | 56.0 | 62.0 |
| 56.0 | 58.0 | 62.0 | 66.0 |
| 60.0 | 62.0 | 66.0 | 70.0 |
| 64.0 | 66.0 | 70.0 | 74.0 |
| 68.0 | 70.0 | 74.0 | 78.0 |
| 72.0 | 74.0 | 78.0 | 82.0 |
| 76.0 | 78.0 | 82.0 | 86.0 |
| 80.0 | 82.0 | 86.0 | 91.0 |
| 85.0 | 87.0 | 91.0 | 96.0 |
| 90.0 | 93.0 | 96.0 | 101.0 |
| 95.0 | 98.0 | 101.0 | 107.0 |
| 100.0 | 104.0 | 107.0 | 112.0 |
| 105.0 | 109.0 | 112.0 | 117.0 |
| 110.0 | 114.0 | 117.0 | 122.0 |
| 115.0 | 119.0 | 122.0 | 127.0 |
| 120.0 | 124.0 | 127.0 | 132.0 |
| 125.0 | 129.0 | 132.0 | 137.0 |
| 130.0 | 134.0 | 137.0 | 144.0 |
| 140.0 | 144.0 | 147.0 | 155.0 |
| 150.0 | 155.0 | 158.0 | 165.0 |
About Metric Clearance Hole Sizes for Bolts and Screws
This metric clearance hole size chart provides standardized drill hole dimensions for bolts and screws in metric units. It includes recommended close fit, medium fit, and free fit holes, along with corresponding clearance hole diameters in millimeters for precise machining and assembly.
Using accurate metric clearance hole dimensions ensures proper bolt and screw seating, correct alignment, and reliable mechanical performance. This reference is useful for engineers, machinists, and designers working with ISO metric fasteners, including:
- Mechanical engineers and product designers creating assemblies in metric units.
- Machinists and technicians drilling holes for bolts and screws with precise tolerances.
- Fabricators ensuring correct fit, alignment, and tolerance in mechanical components.
- Assembly and maintenance professionals referencing standardized metric clearance hole dimensions for reliable fastening.
Key Terms in the Metric Clearance Hole Chart
- Nominal Thread Diameter (mm): The designated size of the bolt or screw thread in millimeters.
- Close Fit: Minimum clearance providing precise alignment between fastened components.
- Medium Fit: Standard clearance allowing moderate assembly tolerance for general applications.
- Free Fit: Larger clearance suitable for easy assembly or components requiring positional flexibility.
- Clearance Hole Diameter: The actual drilled hole size corresponding to the chosen fit type.
Referencing this metric clearance hole chart for bolts and screws ensures consistent part design, accurate drilling, and proper assembly in metric mechanical systems. Correct use of these dimensions improves assembly quality, reduces machining errors, and ensures compatibility with ISO fastener standards.