You signed a Swiss contract with a gross salary in CHF, you live in France, and somewhere in the first three months you are supposed to make a permanent health-insurance choice between LAMal and CMU — in French, against a clock you barely understand. The single number nobody gives you is the one that matters: what actually lands in your account each month, and whether LAMal or CMU is cheaper for you. Net Frontalier is a free, anonymous, bilingual app that answers exactly that. Here is what it does, what it honestly does not do, and how to use it before your droit d'option deadline runs out.
Free, no account, on iPhone and Android.
Your Swiss employer quotes you a gross figure in francs. Your payslip then subtracts a stack of contributions with initials you have never seen — AVS, AI, APG, AC, LPP, NBU — and what you actually receive bears little resemblance to the headline number. If you are an Anglophone frontalier, you are decoding all of this in a second language, often before your first payslip even arrives.
Net Frontalier deducts each of those charges using the official 2026 rates and shows you a plain-language breakdown of every line:
The result is the single figure you actually wanted: an estimate of what hits your account each month. The app shows this before income tax and health-insurance premiums, which it displays separately as reference rather than silently subtracting — so you always know what each number means.
Within three months of starting your Swiss job you exercise your droit d'option — a meant-to-be-permanent choice between Swiss LAMal health insurance and French CMU/PUMa. Get it wrong and you are locked in for the duration of the contract. The problem is that the two systems are priced in completely different ways, so you cannot compare them in your head:
Net Frontalier puts both side by side for your actual salary. It uses an average LAMal figure (real quotes vary by insurer, so treat this as a starting point) and the CMU formula, so for the first time you get an apples-to-apples monthly comparison. For the full rules behind this decision, read our companion guide on LaMal vs CMU.
There is no paywall, no trial, no account. Download it, type your gross salary and canton, and you have your numbers in under a minute — nothing is uploaded.
Because it works in English and French, you are not forced to reverse-engineer French abbreviations to understand your own payslip — a genuine relief if you have just arrived and the whole frontalier vocabulary is new.
If you have children, your family benefits can come from two countries at once, and the rules are not intuitive. Under EU Regulation 883/2004, when a frontalier works in Switzerland and a spouse works in France, France generally pays first and Switzerland tops up the difference (the differential), or vice-versa depending on who works where.
Net Frontalier computes this CAF differential / Swiss family-allowance top-up across the cantons it covers, and it specifically handles the mixed-household rule — the common case where one parent works in Switzerland and the other works in France. Instead of guessing whether you are owed a top-up, you get an estimate of the gap between the French and Swiss allowances for your household.
This is the single most misunderstood point for new frontaliers, so be precise about it:
So the lazy summary you will hear — 'you work in Switzerland, so you're taxed in France' — is simply wrong for Geneva, where the majority of frontaliers actually work. Net Frontalier keeps these straight by canton and never subtracts a phantom French tax from a Geneva salary.
Geneva frontaliers taxed at source may qualify as a quasi-resident (quasi-résident) if they earn at least 90% of their worldwide income in Switzerland. Qualifying lets you file an ordinary Geneva tax return (TOU) and deduct real expenses — pension buy-ins, childcare, alimony, professional costs — which the flat at-source rate ignores. For many that means reclaiming several thousand francs.
Net Frontalier checks whether you cross the ≥90% threshold and flags your eligibility. Be clear on the limit: this is an eligibility flag only, not a tax computation. It tells you the door is open; it does not file your TOU return or calculate your refund. Treat a positive flag as a prompt to look into it (or speak to a fiduciary), not as a finished tax filing.
Two things make the app actually usable rather than just another calculator:
That second point matters for the droit d'option in particular: a one-tap snapshot of 'here is my net, here is LAMal vs CMU for me' is far easier to discuss than a wall of payslip abbreviations.
Honesty about the limits is what makes an estimate trustworthy. Net Frontalier:
Within those limits it does the one thing that is genuinely hard to do by hand: turn a CHF gross number into a realistic monthly picture you can actually plan around.
An estimate is the right starting point. When you are ready to act on it — actually exercise the droit d'option, affiliate with CPAM, or file a Geneva quasi-resident return — you will want guided, document-level help rather than a single number.
That is what the AdminLanding cross-border France–Switzerland toolkit is for: a deeper LAMal-vs-CMU simulation, the affiliation steps, and the forms, built specifically for France-Switzerland frontaliers. Use Net Frontalier to understand your situation; use the toolkit when it is time to file.
Yes — completely free, with no trial, no paywall and no account. It is also anonymous: there is no signup and no personal data is stored. You enter numbers, it returns estimates, and nothing leaves your phone.
Six border cantons only: Geneva (GE), Vaud (VD), Jura (JU), Neuchâtel (NE), Basel (BS) and Valais (VS). It does not cover every Swiss canton, so if you work outside these six the figures will not apply.
It puts both side by side for your salary: an average LAMal monthly premium against your CMU/PUMa cotisation (roughly 8% of income above a 25%-of-PASS deduction). LAMal figures are averages and real premiums vary by insurer (~CHF 350–700), so use it to see the direction of the answer, then confirm with a real quote.
No. Geneva taxes frontaliers at source in Switzerland (impôt à la source), so you are not taxed in France on that salary. Only the 1983-accord cantons — Vaud, Neuchâtel, Jura, Basel, Valais — are taxed in France. The app keeps this distinction by canton.
Quasi-resident status lets a Geneva frontalier who earns at least 90% of worldwide income in Switzerland file an ordinary return and deduct real expenses, potentially reclaiming several thousand francs. The app only flags whether you appear eligible — it does not file your return or compute the refund.
No. It is a calculator, not a government portal. It does not submit your droit d'option, your CMU affiliation or any tax return. It estimates the numbers so you can plan and then act through the proper channels.
For more practical insights on this topic, explore our related articles:
Conclusion: The hardest part of becoming a frontalier is not the work — it is making a permanent health-insurance choice, in a second language, around a salary number nobody has actually shown you. Net Frontalier closes that gap: free, anonymous, bilingual, and honest about its limits. Use it to see your real monthly net, to settle the LAMal-vs-CMU question for your own salary, to check whether you are owed a family top-up, and to find out if Geneva quasi-resident status could put francs back in your pocket. Then, when it is time to file, move to a guided toolkit. Get the numbers first — everything else is easier once you can see them.
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Julien is a European expat guide sharing practical, tested advice for navigating life abroad. Contact: [email protected]
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