Home Article index Newsletter

Deze pagina in het Nederlands

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

A new tool: Github VBA exporter
I've added a new tool (in beta!!) to my download section called Github VBA Exporter. This utility enables you to export all components from a VBAProject to a user-selectable set of folders. Very useful if you need to upload the contents of a VBA project into Github. The tool generates a textfile which contains all properties of ...
Wed, 13 Jan 2021 10:30:00 GMT

Update: Name Manager
Name Manager has just been updated to build 675. You can now filter for Lambda names and you can edit name comments
Mon, 14 Dec 2020 13:55:00 GMT

Update: RefTreeAnalyser
RefTreeAnalyser 2.0 has just been updated. Added two new options: 1. Generate a Table of Contents and 2. Added a feedback button which takes you to a small survey so you can tell me what you like and what you do not like.
Fri, 04 Dec 2020 11:00:00 GMT

Video: Smart Macro Recording
I presented during the Excel Virtually Global conference in July 2020, Here's the recorded video: Smart VBA Macro Recording
Mon, 24 Aug 2020 16:15:00 GMT

Updated article: Prevent Open Event
I have updated my existing article on how to prevent Open events from running as Microsoft has changed the way Excel responds to the Shift key being held down (it now ignores it).
Thu, 13 Aug 2020 16:15:00 GMT

New article: Enabling Drag and Drop between two Listboxes on a VBA Userform
I have added a new article today which shows how to enable drag and drop between two listboxes on an Excel userform
Wed, 10 Jun 2020 10:30:00 GMT

Nieuw artikel: Gegevenstypen gebruiken in Excel
Ik heb een artikel toegevoegd over het gebruik van Gegevenstypen in Excel.
Thu, 21 May 2020 16:00:00 GMT

New article: Using Data Types in Excel
I have added a new article today about data types in Excel.
Fri, 08 May 2020 15:20:00 GMT

Show All news