As you might know, I like to understand how things work. This applies very much to physical, technical things, but also to laws and regulations, and then in particular my income tax. After the year ends, the Belastingdienst software can calculate your taxes for you, but I would like to be able to understand and predict that calculation. Especially since I started as a self-employed contractor, it made sense to know the impact of some choices (and to predict my taxes so I am not surprised by a big bill).

For this, I created a spreadsheet to do this calculation. I've been updating the spreadsheet every year with the latest regulations and tariffs and it has worked for me pretty well. I have long intended to share this work, but never got around to it until a former colleague showed interest in the spreadsheet, which was a good reason to finally clean it up and put it online.

The spreadsheet can:

• Calculate income tax (Inkomstenbelasting, that anyone needs to pay) and ZVW (Inkomens-afhankelijke bijdrage Zorgverzekeringswet, paid by self-employed people directly, for employees their employer handles this).
• Calculate how much Zorgtoeslag you are entitled to, if any.
• Calculate your pension allowance (Jaarruimte & Reserveringsruimte).
• Take into account Hypotheekrenteaftrek, Investeringsaftrek and aftrekbeperkingen.

In general, the yellow-colored cells can be filled with personal info, the grey-colored cells contain year-specific numbers.

Some caveats:

• The spreadsheet is for Dutch taxes and written in Dutch (I considered writing this blogpost in Dutch as well, but that would be the first, so I stuck to English here).
• The spreadsheet works well if you are just employed or just self-employed. When combining both, there might be some details that will be different.
• I have used the spreadsheet with a partner, but it should also work fine if you report your taxes alone (I think only the Zorgtoeslag part is incorrect).
• Everything assumes you have not reached the AOW-leeftijd yet. If you have, a ton of things change.
• The spreadsheet goes back all the way to 2010, but the earlier years are less extensive and less nice.
• I have verified the calculations are correct by comparing with my own income tax report, but for the most recent year where I did not report yet, and for parts of the spreadsheet that do not apply to my situation, there might still be errors.
• No warranty or guarantees of any kind. This is just a tool for me that might save others time, but be sure to check everything against your situation.

I usually update the spreadsheet in the first half of the year with the new numbers for that running year. I will try to publish the updated spreadsheet here when I do, but if you are looking for a more recent version that is available, feel free to drop me an e-mail to ask (I might just have forgotten to put the new version online). Also, if this spreadsheet is useful to you, I would appreciate a shout out in the comments, via mail or on Mastodon.

The current spreadsheet is updated until 2026 (checked against the report program until 2025) and can be downloaded here:

>> Download Spreadsheet (ods) <<