About Calcosmo
Calcosmo is a collection of free calculators for everyday questions about money, work, home, cars, dates, health and percentages, available in English and Dutch. You will currently find 65 calculators in English, from week numbers, VAT and mortgages to currency conversion, age and fuel costs, plus a set of Dutch-specific tools for expats and anyone dealing with Dutch taxes, such as the Dutch road tax, company car tax and take home pay calculators.
What we care about
- An explanation with every result. A number without context only helps you halfway. That is why every calculator comes with the formula, worked examples and answers to frequently asked questions, so you can check the result and understand what happens.
- Reliable sources. Where official rates matter, such as Dutch road tax, company car tax or income tax brackets, we use the figures published by the Dutch government and tax authority. The source and the date we last checked it are shown directly below the calculator.
- Privacy. All calculations run in your own browser. We don’t ask for an account and we don’t store what you enter.
- Fast and accessible. Pages are light, work on phones and computers, and can be used entirely with a keyboard.
How we work
Mathematical formulas, such as those for interest, loans, percentages, area and volume, are checked with worked examples and automated tests with fixed example values and edge cases. Exchange rates come from the European Central Bank’s daily reference rates. When rules change, for example at the turn of the year, we update the tools concerned and the date on the page.
Our calculators give an indication. For decisions with major financial, tax or medical consequences, we recommend asking a qualified professional, such as an accountant, tax adviser or doctor. Please also read our disclaimer.
How we keep this site free
The calculators are and will remain free. To cover hosting and maintenance, we show ads from Google AdSense. Ads only load after you give permission in the cookie banner. Read more in our cookie policy and privacy policy. Advertisers have no influence on the content or results of our calculators.
Who we are
Calcosmo is a trade name of F&J Partners VOF, KvK 97743771. Do you have a question, an idea for a new calculator or did you spot a mistake? We would love to hear from you via the contact page.