About Helvon
Helvon publishes free Swiss calculators — mortgage, taxes, cross-border salary, electricity — built on official public data. This page says who writes, where the figures come from, when they are updated, and what this site does not claim to be.
Why this site exists
Swiss public data is excellent and almost unusable as it comes. Electricity prices live in a federal data warehouse queried in SPARQL; tax scales in an administration API; mortgage financing rules in banking guidelines. Each source answers a precise technical question, but none answers the one people actually ask: how much, for me, concretely?
Helvon does that translation work. One question per page, one figure in large type, and the formula right below it so you can redo it by hand if you want to.
Who writes
Jim Baumgartner — La Tour-de-Trême, canton of Fribourg.
I design and code the calculators on this site myself, from the official sources cited on each page. I am neither a financial adviser, nor a tax expert, nor a broker: I have no product to sell and no commission to earn. That is precisely why every tool shows its formulas and leaves its parameters editable — you do not have to believe me, you can check.
How the calculators are built
Each tool rests on an official source, named on its page:
| Borrowing capacity and income needed | Swiss Bankers Association guidelines and standard banking practice (5 % theoretical rate, costs capped at 33 % of income, 20 % equity) |
| Tax comparison | Official API of the Federal Tax Administration — scales, municipal multipliers, deductions; 2,110 municipalities |
| Cross-border net salary | Federal Social Insurance Office (OASI/DI/LEC), SECO (unemployment insurance), Geneva tax administration (withholding tax), the 1983 France–Switzerland agreement |
| Electricity cost and price | ElCom, via Swiss Confederation open data (LINDAS); 2,123 municipalities |
| Electric versus petrol | ElCom prices for electricity, market averages for fuel |
| Pillar 3a | Annual ceilings published by the Federal Social Insurance Office |
| Leasing | Standard annuity formula with residual value |
| CHF/EUR converter | European Central Bank reference exchange rates |
No paid API, no purchased data, no commercial partner. When an administration publishes a calculation method, I reproduce it and validate it against its own official calculator; when the cantonal mechanics are too specific to reproduce — which is the case for Geneva, Vaud and Valais on income tax — I query the official API directly and interpolate pre-computed grids, stating so on the page.
When the data is updated
| Electricity prices | once a year — operators publish their tariffs by the end of August for the following year |
| Tax scales and municipal multipliers | once a year |
| Social contributions and pillar 3a ceilings | once a year |
| Property purchase costs by canton | estimates, revised when flagged |
| CHF/EUR exchange rate | entered by you; the reference rate shown carries its date |
Every page carries the reference year of its data. If you come across a stale or wrong figure, write to me: it is the most useful message I can receive.
What Helvon is not
The results are estimates meant to prepare a decision, not to replace it. They do not know your full situation and have no contractual value. For a real commitment — a mortgage, a tax return, a change of tax regime, a request for recalculation — the competent parties remain your bank, your cantonal tax administration, or a professional authorised to advise you individually.
How the site is funded
Helvon is free and requires no registration. The site asks for no personal data, resells no contacts, and places no affiliate links to banks, insurers or comparison services. It is intended to be funded by display advertising, clearly identifiable as such and separated from the content. No advertiser has any say over what is written here.
Corrections and suggestions
An error to report, a missing municipality, a tool you wish existed? The contact page explains what to write and what I cannot answer.