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Rule Numbers

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Estimating Water Velocity

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Rule Number Lookup Tables


Rule Number Lookup Tables

Lookup tables on this page provide rule numbers for a wide range of sinking line grain weights, diameters, and water temperatures. The 55 degree fresh water table is a good standard for most purposes.

Rule numbers are slightly higher in colder water and salt water and slightly lower in warmer water. We offer additional tables below for those who want more exact information.  However, the differences are relatively minor compared to the standard 55 degree fresh water table. 

For "in-between" rule numbers, or for unusual fly lines that are outside the ranges covered by these tables, use our sink rate and rule number calculator.