Typical Fly Usage For Leader Sizes
To calculate leader size a time used formula is to divide the fly size by 3, this gives you and approximate tippet size.
For example for a size 16 fly 16/3 = 5.33 so recommended leader diameter should be 5x to 6x
Diameter (mm) | Diamteter (inch) | Butt Diameter (mm) | Butt Diameter (inch) | Typical fly hook size useage |
0.789 | 0.011 | 0.64 | 0.025 | 2 |
0.254 | 0.010 | 0.58 | 0.023 | 4-8 |
0.229 | 0.009 | 0.56 | 0.022 | 6-10 |
0.203 | 0.008 | 0.53 | 0.021 | 10-14 |
0.178 | 0.007 | 0.53 | 0.021 | 12-16 |
0.152 | 0.006 | 0.5 | 0.02 | 14-18 |
0.127 | 0.005 | 0.43 | 0.017 | 16-22 |
0.102 | 0.004 | 0.43 | 0.017 | 18-24 |