Published May 23. 2016 - 7 years ago
Updated or edited Feb 12. 2023

LeaderCalc 2016

Many years ago we launched LeaderCalc, the spreadsheet that helps you dimension your leaders. It was last updated almost 10 years ago. It's time for a new version.

Check out the latest update: LederCalc 2023
LeaderCalc has been updated to an online tool!
You can try the new tool here and read more about how to use it here.

LeaderCalc 2007
LeaderCalc 2007
Martin Joergensen

GFF partner Steve Schweitzer introduced the first version of his LeaderCalc spreadsheet back in 1998. Yes, almost 20 years ago!
Back then it was groundbreaking software, which allowed you to calculate the section lengths of your knotted leaders based on a large number of leader formulas including some of the best known and most popular leader designs available.

Microsoft Excel

The program was a spreadsheet, which you downloaded and could run in Excel, the spreadsheet software that came with the Microsoft Office package. In those days MS offered a so called runtime version of Excel, which non-Office users could get for free. It couldn't do much else than running finished spreadsheets, but was just what non-Office people needed for LeaderCalc.
The spreadsheet file was upgraded with more and better facilities in the early 2000's, and Steve published it on a CD that was delivered with Joseph Kissane's book Drag-free Drift, published in 2001. The system got another update in 2007, but has been static since then.
It's still a very popular part of the Global FlyFisher, but some users are experiencing problems with the file when used in the free software packages Open Office or Libre Office, and time has come to take it into the online age and make it a purely online based tool.

The form
The form
Martin Joergensen

LeaderCalc 2016

The new version of LeaderCalc is very different from Steve's original spreadsheet, but still builds on the exact same founding data: the leader designs, formulas and basic calculations. The system is currently capable of generating more than 2,500 different leader formulas, but more will probably be added as I get my hands on new formulas.
The spreadsheet style has been ditched, and the system is now one simple form, which allows you to choose the same combination of characteristics as the original: length, tippet size and line weight. Using the selected data, the system will find leaders that can be made to the selected specifications.
You can also filter by type of leader, meaning that you can choose to see dry fly leaders only, which in combination with the other filters gives a more precise selection.

The recipes

Once you have selected your specs and submitted them, you will get a range of leaders presented with name and type – and comments if they exist – and a complete list of the mono sections you will need, length and thickness for each of the leaders you have found.

Your saved leaders
Your saved leaders
Martin Joergensen

You even get a nice schematic presentation of the leader, showing its sections and taper visually.
If you wish you can isolate the exact leader you want by clicking the link Show this only, and print it, ready to use for measuring and tying. When you are looking at a single leader, you can click the link Show all variations to get... yes, you guessed it: all variations of that leader varying tippet and length.

My leaders

You can save any leader for later. Clicking the Save link next to the schematic drawing adds it to the My leaders page where you can see all your saved leaders. A small number in the LeacerCalc menu indicates how many leaders you have saved. If you are a GFF user and logged in, the leaders will be saved with your account data, and will be available the next time you return and log in. I you aren't logged in, your saved leaders are registered in a cookie in your browser, and when you return later, the same leaders will still be available - unless you delete the cookie, of course. Leaders saved on your My leaders page will have a Remove link in stead, used for... drum roll... removing it again. Tadaaa!

All that remains is for you read through the recipe and to cut out suitable pieces of mono and tie them together. The process has already been described by Steve in the article on production tying of leaders.

Another approach

You can “browse” the leaders by seeing them listed by name. This gives you an option to find different named leaders or simply get an overview over the selection. Another way to list them is sorted by:

This is a new way of looking at leaders and they might not all be very useful for finding the exact leader you need, but these approaches are great for seeing how many different designs exist within the different groups and comparing them.

Leaders by name
Leaders by name
Martin Joergensen


I have set up some limitations in the system. Since you can select to see all variations of a certain criteria – all categories, all lengths etc., you can now make a selection in the form, which will potentially generate a lot of leaders – A LOT!
Seeing all 2,500+ leaders makes no sense and takes a lot of calculation and load time, so that is blocked. But you can combine one specific criterion with all options of the others. It can still take time and generate hundreds of leaders for some combinations, but it can be done.
Warnings will be issued if you select a combination that has the potential to take time to calculate or give a lot of results. You can still give it a spin if you want. The GFF server probably has more patience than you if you start generating a large batch.

Start tying!

Apart from these limitations, you can now generate leader recipes galore and start tying your own knotted leaders. Should you have a formula for a great leader, which is not in the system, feel free to contact me, and I will seriously consider adding it. It can be your own design or something well known. There's room for them all.

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New Leadercalc...

Good to see the new version - very easy to use. Another way hardcore detail-oriented fly fisherfolk can personalize their enjoyment. Bravo!

LeaderCalc 2016...

I have been using the downloadable version for years, and I am pleased to see a new version which makes simpler to use. Thank you for a fine tool.

Jimmie Roop


I've used LeaderCalc since 1970 and love it. Used mostly for wet & dry fly fishing, Steelhead & Trout. I was weeding out my favorite's & Bookmarks which have grown quite large over the years, clicked on "The Global FlyFisher's" web page just to see what's new and found that you updated "LeaderCalc" Downloading it today & can't wait to see what's new. Thank's guy's for such a fine product. hcmiller

Martin Joergensen's picture



I'm glad you like LeaderCalc, even though I'm quite sure that 1970 is a bit exaggerated. The system is much younger than that, but anyhow... And with regards to the new version, you will not need to download anything, but can use it directly from the site.



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