Welcome to the website of JKP Application Development Services

What I do


I offer services pertaining to any aspect of Excel and VBA. My Services page shows you examples of services I provide. You will also find a list of recent projects there.


I develop bespoke Excel tools for customers and also Excel add-ins for the general public, like my spreadsheet auditing tool RefTreeAnalyser. Check out products I have developed.


I offer both pre-scheduled trainings and custom-made courses. Content of trainings can be adapted to your needs. If preferred we also offer any course as an in-house training.


Subscribe to our news letter or check out the archive. There is no set frequency, I just post something when I have time. In any case, it is all about Excel.

Free Excel tools

I develop custom-made applications using Microsoft Office Excel® and VBA and Access and VBA to their full extent. Have a look at various (free) downloads, some of which have become the de facto standard for Excel developers around the world.

Who is Jan Karel?

Would you like to learn more About me? On this page you can get to know me a little better and also find a short list of presentations I've given over the past years.

What's new on this site

English and/or Dutch content

Update: RefTreeAnalyser

RefTreeAnalyser has just been updated to version 3.1, build 187. RefTreeAnalyser now also enables you to move your mouse over a sheet and see all cells with the same formula highlighted.

Thu, 22 Sep 2022 14:00:00 GMT

Update: Name Manager

Name Manager has just been updated to build 700. Fixed an issue pertaining to renaming and using the pickup function for users using an international keyboard

Thu, 22 Sep 2022 14:00:00 GMT

Update: Excel File Remediation Utility

The Excel File Remediation Utility has been updated to build 133. Fixed a bug in the logging routine which causes errors when Windows is using a period as the date separator. Please manually download the new version as it looks like the update process also causes errors.

Tue, 02 Aug 2022 10:55:00 GMT

Update: Name Manager

Name Manager has just been updated to build 696. Name Manager now works together with Charles Williams Lambda Explorer if you've got that installed

Tue, 26 Jul 2022 10:50:00 GMT

Update: Name Manager

Name Manager has just been updated to build 695. Fixed a bug regarding listing all names on a protected workbook

Mon, 18 Jul 2022 13:15:00 GMT

Updated : Flexfind

Flexfind has been updated: Added a textbox which displays the text in which your search string was found. Highlights the search string.

Wed, 13 Jul 2022 10:45:00 GMT

Update: Name Manager

Name Manager has just been updated to build 694. IT IS NOW FULLY COMPATIBLE WITH MAC EXCEL!

Wed, 13 Jul 2022 09:15:00 GMT

Updated : Table Tools

I have updated the TableTools add-in. I'm updating the add-in so it also works on Mac Excel

Mon, 06 Jun 2022 10:45:00 GMT

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