Found a bug, have a question, or an idea for another calculator? We are glad to hear from you. Email is the quickest way to reach us.
kontakt@prozentrechner-online.com
For bug reports, please include the page concerned, the values you entered and the result you expected where possible. That helps us reproduce and fix the problem faster.
Response time
We read every message and usually reply within a few working days. As the site is run as a private project, it may occasionally take a little longer.
What we can help with – and what we can’t
- Happy to help with: questions about the calculators, reports of calculation or display errors, suggestions for new features, accessibility feedback.
- Not possible: individual legal, tax or financial advice, or binding review of specific contracts, tax cases or salary negotiations. Please consult a qualified professional for those.
The answer may already be here
Many percentage questions – such as the VAT trap, the rule of three, or the difference between percentage change and percentage difference – are already explained in detail. It is worth a look:
Privacy
If you email us, we process your details solely to handle your request. For more information, see our privacy policy.