Last updated: August 30, 2026
Write to
There is deliberately no form. A form would mean adding a third-party service to receive your messages, and with it one more purpose to declare in the privacy policy. An email goes straight there and brings nobody along the way.
This is run by one person, so a reply takes a few days. Bug reports jump the queue ahead of everything else.
What to write about
What helps most, in order:
- A calculation error. If the result does not match your payslip or your country's official calculator, send the inputs — gross, country, region and household — and it can be reproduced.
- A figure that is no longer current: a band that moved, a new contribution ceiling, a credit that was revised.
- A missing country, or a part of the tax system of one already here that is not modelled.
- Something unclear, badly rendered on your screen or poorly translated.
Privacy and advertising
This is also the address for exercising your data protection rights and for any question about the ads. What can realistically be acted on is set out in the privacy policy, and what your browser stores, in the cookie policy.
What cannot be answered
Personal tax questions. No advice is given and individual cases are not reviewed: I am not a tax adviser, and answering that by email would do you a disservice. For your own situation, a qualified professional or the tax authority itself.
Nor do you need to send real figures to report a fault: an approximate example that reproduces it is enough, and better for both of us.