Use the below bolt hole clearance chart for Metric size bolts and screws.
This table shows how to determine the clearance hole size for a bolt.
For example, an M3 bolt with a medium fit would have a 3.4 mm clearance hole.
| Nominal Thread Diameter/mm |
Clearance Hole Sizes/mm | ||
| Close Fit Series |
Medium Fit Series |
Free Fit Series |
|
| 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 |
| Nominal Thread Diameter/mm |
Clearance Hole Sizes/mm | ||
| Close Fit Series |
Medium Fit Series |
Free Fit Series |
|
| 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 |
| Nominal Thread Diameter/mm |
Clearance Hole Sizes/mm | ||
| Close Fit Series |
Medium Fit Series |
Free Fit Series |
|
| 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 |
Download the Metric Clearance Hole Chart to save the chart as a PDF – useful to print out to have next to your tools.
Want to determine what size clearance hole for Imperial, for example, 3/8″, then check out our chart here.
Reference:
- Oberg, E., Jones ,F.D., Horton H.L., Ryffel H.H., (1976). Machinery’s Handbook 20th Edition. Industrial Press Inc, 1446-7.
10 thoughts on “Clearance Hole Size for Bolts and Screws (Metric)”
Love your work here, Mate! keep it up!
Thank you Allen!
Love your work! Keep it up!
Made my day! Been looking for such a chart.
Thanks! Great work and a great resource
Nice 👍
Thanks a lot.
Very helpful – thank you!
Thank you this chart is very simple and good to explain
Thank you so much, great chart that I now have hanging in front of me for reference.