ziffaro is built by one person: Christoph Ballmer. Every calculator on this site was written, checked and published by me, and my name is on the pages where money and health figures are involved. If a number here is wrong, there is exactly one person to hold responsible for it.
That is a deliberate trade. A single builder means every tool gets read line by line before it ships, and it means the method can be written down in full rather than described in the abstract. How a figure gets onto this site — which source, which verification, which stated limits — is set out on the methodology page.
Who builds these tools
My craft is web development and project delivery. Over more than two decades I have shipped digital projects end to end — concept, programming, finished product — for internationally active companies and for smaller firms around Basel. I hold a Master in Marketing Management.
A formative part of that path lies in the banking sector: for several years I led digital marketing and online communication for Swiss banks. That work is where the habits behind this site come from — the assumption that a published figure needs a traceable source, and that the caveats belong next to the number rather than in the small print.
Christoph Ballmer on LinkedIn and Xing.
What that background covers — and where a licence takes over
Building the tool, reading an IRS publication correctly, reproducing a documented example to the cent and stating plainly what a result leaves out: that is the work I do here, and it is the work this site stands on.
A US tax or medical licence is a different thing, and this site treats it as one. Where a page carries a professional review, it names the professional, their credential and the date of the review, with a link you can check. A page without that line has been built and sourced as the methodology page describes and claims nothing beyond it. You can tell the two apart by looking — which is the point.
For anything that turns on your own circumstances — your credits, your state and local situation, your medical history — a CPA, an enrolled agent or a clinician is the right next step, and the tools say so where it matters.
Found an error?
Corrections are welcome and they get shipped. Send the tool, the number you got and the number you expected to info@ziffaro.com. Reports that identify a real error are acted on.
The company behind it
ziffaro is operated by Honeygoat GmbH, Kägenstrasse 21, 4153 Reinach, Switzerland (Reg. CH-270-4005459-5). Honeygoat runs a small portfolio of focused calculator and tools sites; ziffaro is the US-market member of that family.
All calculators and tools on ziffaro are non-binding aids. Results are guideline values for general information, provided without warranty, and are not a substitute for professional, legal, tax or medical advice.