Independent buying guides for fly fishing

Tippet Size Calculator

Tippet that is too thick makes a small fly swim unnaturally, too thin and you break off fish. Enter your hook size.

Result

Tippet size
5X (or 4X to 6X)
Diameter
about 0.006 in
Typical nylon strength
4-5 lb

Go one size heavier for big fish, heavy structure or streamers, and one lighter for clear, slow water and spooky trout.

How this calculator works

The rule of 3: divide the hook size by 3 to get the tippet X size, then use that size or one either side. Diameter in inches is roughly 0.011 minus X divided by 1000. Breaking strengths vary by brand and material, so the range shown is typical nylon.