Published May 8. 2016 - 7 years ago
Updated or edited Dec 6. 2023

About LeaderCalc

LeaderCalc was originally developed in the late 1990's and up until about 2006 by Steve Schweitzer as a spreadsheet, and this is an adaption for web based online use made by by Martin Joergensen in 2016. You can read the intro article here. Unlike the original version, this new web based version is now and then updated with new formulas and even new features.

You can use the web based version in several ways:

Using the form

Use the form to enter the specifications you require of your leader:

  • Category
  • Length
  • Tippet thickness
  • Line weight

When submitting the form you will get a list of the leaders that match your selected criteria. Please notice that it's better to be specific than general. The more "All" options you choose the more leaders you get, rendering the selection very wide. The system can calculate almost 2,800 leader combinations and you want to narrow the criteria down to get as useful a selection as possible.
You can select to see the leader formulas in inches (Imperial) or centimeters (Metric). The system will remember your choice, and you can always change back and forth when viewing leader formulas.


December 2023
You can now find leaders similar to the one you are looking at. In the formula table you will find a link called "Show similar", which will lead to a page with leaders matching in length and tippet. You will see all kinds of leaders, but you can narrow them down by selecting a line weight or a category - or both. This might help you find some alternatives to a leader that you found interesting.

February 2023
There's a whole bunch of new leaders added in a brand new category: Moderne nymphing leaders, as well as a number of new functions. You can read about these updates here.

December 2019
The system has been updated with some new facilities and a few new leader formulas.
In the pages with leaders based on sections, lengths, tippets and line weights, the lists have now been made collapsible and expandable, and the lists are arranged by leader type for better overview. They used to be simple lists. The new system gives you a better chance of finding a leader that suits your needs.
Also, a few new leader formulas have been added, among them some distance/competition leaders.

Saving your favorite leaders

You can save your most used or favorite leaders so that you can easily return to them later. Whenever you see a leader formula, there's a handful of options below the formula to the right, and one is "save".
Click this, and the leader is saved and can be found under the menu item "My leaders". If you are registered and logged in, your leaders will be saved with your user data. If you aren't, they are saved in a so-called cookie, and will only show on the device you saved them on, and as long as the cookie isn't deleted. If cookies are disabled for GFF, you cannot save your personal leaders.

When a leader is saved in your leaders, it will be marked with a checkmark, and the "save" option will change to "remove". Clicking on this link will remove the leader permanently from your leaders.
You can always add it again later.

Browsing by specs

You can also browse leaders by more general criteria:

By category

Select the category of leader you want, like dry fly, streamer or nymph and see a list of named leaders for this purpose. Click the one you want to get the formula variations available.

By name

See a list of all leaders and select the one you want to see details about.

By sections

This will list the leaders by sections - or complexity if you will. The simplest leaders have just 2-3 sections while the most complex ones consist of up to 12 individual pieces of mono.

By length

This lists all the available lengths from 3' to more than 17' and a list of all leaders available in each length with half foot intervals. Click on the leader you want to get tippet variations of that leader for the specific length.
NB: Notice that length can vary slightly compared to the nominal length for the given leader due to conversion and rounding errors.

By tippet

This lists all tippet thicknesses available: 1X, 2X, 3X and so on. Click a leader name to see variations in length for that leader formula and tippet.

By line weight

LeaderCalc has leaders for lines in the 0 wt to 12 wt range, and you can browse them with the line weight as a starting point,

Tippet considerations

Please notice that these leaders are shown including the tippet - the terminal piece of mono to which you tie your fly - unless otherwise noted. Oftentimes the term leader just refers to the tapered part of the leader/tippet combo, and you add the tippet to that. In this case you tie your fly to the last section of the leader in the formula. Consider extending this section a bit compared to the formula in order to have some material for changing flies a few times before having to change the tippet section.