LAMal or CMU? Get your monthly cost for both

The deadline beats the arithmetic

The 3-month window runs from the start of your work in Switzerland, from your move to France if you already worked in Switzerland, or from the grant of a Swiss pension. The form, stamped by your CPAM (part 6, whichever system you choose), must REACH the competent Swiss authority before the deadline. The CPAM does not forward it: you send it yourself. The stamp can take weeks: take it to the CPAM as early as you can. For Swiss and EU nationals, without a form within the window, the Swiss authority affiliates you to LAMal (Swiss health insurance) automatically; a frontalier of another nationality outside the EU/EFTA/UK is insured in Switzerland only on request (OFSP). The option is exercised once and is irrevocable. A new option opens only on resuming work in Switzerland (e.g. after a period of unemployment), moving to France, or passing from worker to recipient of Swiss pensions only. A change of employer without unemployment, a marriage, a divorce or a birth does not reopen it. If you had chosen (form stamped by the CPAM, or a LAMal contract) but the Swiss authority was not informed within the 3 months, some cantons cancel the automatic affiliation on request — Geneva: « Annulation d'affiliation d'office » form, to be sent to the SAM without delay (ge.ch). Other cantons: not verified.

Where you want to be treated

LAMal gives you care in Switzerland and, with your S1 registered at the CPAM, in France. Under the French system, care in Switzerland is limited to emergencies and medically necessary care during a stay (European card); planned care there needs prior authorisation (S2 form). The cost and the place where you want to be treated are the two sides of the comparison; the choice is yours.

Household size moves the answer

This is the structural difference between the two systems. LAMal charges a premium for every insured person — each child adds roughly 148 CHF a month. PUMa/CMU is a single contribution on your income that covers the household regardless of size. A couple with three children therefore sees a very different result from a single frontalier on the same salary, which is why the calculator asks for dependants rather than assuming.

The 2028 reform under way

The revision of the ordinance on risk compensation in health insurance (OCoR), put out to consultation by the Federal Council until 3 December 2025, provides for including insured persons living abroad — frontaliers included — in risk compensation from 2028, as Parliament decided when revising the LAMal. According to the FOPH, the inclusion « will lead to an upward trend in premiums for persons insured in countries with a high proportion of cross-border workers »; no figure is given.

Transmitting your choice

Whatever you choose, the CPAM of your place of residence stamps part 6, then you send the form to the Swiss authority. If you live in the Haute-Savoie, the CPAM de Haute-Savoie runs a téléservice for Swiss frontaliers, frontaliers-suisses-cpam.fr, to hand it the form. Outside the Haute-Savoie: give the form to the CPAM of your place of residence (front desk or ameli account).

Sources (checked 30/09/2026): ameli.fr Haute-Savoie — Travailleur frontalier suisse · ge.ch — Droit d'option pour les frontaliers résidant en France (« Si vous habitez en Haute-Savoie »), maj 05/05/2026 · Préfecture de la Haute-Savoie — Frontaliers franco-suisses : droit d'option