X? What the heck does X mean?

Dave Jolie Nov 29th 2017

Well 11, you didn’t know that?

Seriously. I get this question a lot as it pertains to leaders and tippet. The system is really counter intuitive. The smaller the number, the thicker and heavier the material. The larger the number, the finer and lighter the material.

Makes no sense to me. It’s like wire and gauge measurements I suppose.

So what about X?

Tapered leaders are pretty standard these days in fly fishing. The leaders are extruded from a heavier butt section down to a fine tippet section. The X stem on leaders refers to the tippet section of the material where you tie the fly on.

Tippet, on the other hand, is the same diameter throughout, so it refers to the entire length.

The X system is used to measure the diameter.

Don’t laugh here, but X is equivalent to the number 11 like I mentioned above. To get the diameter in thousandth of an inch, subtract the number before the X from 11. For example, 5X tippet would be 11-5 or 0.006” of an inch. 8X……11-8 or 0.003” of an inch.

Check out the table below:

8X	0.003”
7X	0.004”
6X	0.005”
5X	0.006”
4X	0.007”
3X	0.008”
2X	0.009”
1X	0.10"

Manufacturers also assign a pound test to most leaders and tippet these days too. This can make your selection a bit easier.

If you’re going for big fish in off colored water, 1X or 2X might be one the table for you. Gin clear, mountain stream for trout……you might be into 6X or 7X.

I hope this makes sense for ya. It’s a crazy system really, but it’s the one we got. Here's a good guide for ya