Published Feb 3. 2023 - 1 year ago
Updated or edited Dec 7. 2023

How to use LeaderCalc

This article covers how to use the online fly fishing leader caculator LeaderCalc for creating your own perfect custom made hand tied leaders

The most advanced and comprehensive fly fishing leader tool online ... well, basically anywhere!

LeaderCalc is a tool that helps you make your perfect and optimized fly fishing leader.

I helps you calculate the length and thickness of the pieces needed to make a sectioned hand tied leader.
This article leads you through the process step by step.

The purpose of the tool is to provide you with precise measurements for the sections that go into a hand tied knotted leader.
The tool lets you enter the basic information about the leader you need like rod weight, leader length, purpose, tippet and more. Based on this information the tool will show you a number of leader types, from which you can choose one and see the different variations of that specific leader formula.
It will list in detail the needed thicknesses and lengths of the sections you will need. All you have to do is tie them together.

Let's go through the process

Imagine that you need a leader for some hopper fishing done with a 9 foot 5 weight rod, and the tippet you want is an 3X (because you of course expect some fierce strikes from some large fish!).
3X tippet (or .008"/0.20 millimeters) will typically suit flies in the range #6-#12, so you will most likely be fine there.
You are casting fairly large and bushy flies, oftentimes in windy conditions, so you don't want to be too ambitious on leader length, and settle for one rod length, in other words a 9 foot leader.

So we have some basic info:
Leader length: 9 feet
Desired tippet: 3X
Rod weight: 5

We enter this into the formula and press Find leaders

34 found
34 found
Martin Joergensen

The suggestions

Out comes a number of suggestions. Right now no less than 34, which might seem a bit daunting at first. You can go through them to see if some appeal to you more than others, but you can also select to refine your search and add a leader type. Dry fly could be one obvious option, but Panfish/bass is another. The bass leaders are often suitable for heavier or larger flies than dry fly leaders.

Dry fly leaders will give you five suggestions while there are four panfish/bass leaders in the specified range.

We select the dry fly leaders, and GFF partner Steve Schweitzer's 4-Segment Perfect Taper seems appealing, and we now have some options.

  • Click on the name, and you see all variations. there are 27 with varying lengths and tippets.
  • Click on Show this only, and you see the single 9' 3X tippet leader you were looking for.
  • Click on Show similar, and you see a list of leaders matching the clicked on length and tippet
  • Click on Save, and you can return to this leader later through the link My leaders in the top.
Variations with one saved
Martin Joergensen

In all of these you have the recipe for a 9' 3X leader:
54" of 0.0200 (08X)
27" of 0.0150 (03X)
14" of 0.0110 (0X)
14" of 0.0080 (3X)

or in metric:
137 cm of 0.50 (08X)
69 cm of 0.38 (03X)
34 cm of 0.28 (0X)
34 cm of 0.20 (3X)

These are the sections you need to build the leader. Four pieces of monofilament in the listed thicknesses and lengths.
But before you start cutting, read the next section!

Making the leader

You will need the above lengths in the final leader, but since we're tying these sections together, you will need more than the listed lengths. Add 2-4 inches or 5-10 centimeters to each length for knots and tags (which will be trimmed off) - depending on how long tags you want to work with. Barrel knots are easier to tie if you have longer tags. The better you get, the shorter tags you need.

Use a ruler or a measure tape while tying, and start from the butt, tying on section two. This is the easy part since no measures are necessary here as long as the knot doesn't use too much line.
For the next section - number three - you need to be a little more precise. Measure where the knot should end up on section two, and maybe mark it with a marker. Try to place the second knot on this mark. Take into consideration that the pieces become a bit longer when tightening the knot. Since this is a four section leader, the last section is the tippet, and that goes on section three in the same manner, but can be left without cutting to any length. That can be done by the water.
There's room for variation in most leaders, and should you be off by an inch or two, don't worry! Your leader will work fine anyway.

Depending on your setup you can make a Perfection Loop on the butt or tie it directly onto your fly line using a nail knot. Using a loop requires that you fly line has a loop too.

.... to be continued ...

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