The Swiss authorities online
The expiry date of your passport or ID card is marked in or on the document. Make sure you renew your travel documents in good time.
How much will your new passport or identity card cost and how long is it valid?
You can apply for a temporary passport in an emergency.
Bear in mind that to enter certain countries you may need a passport that is valid for far longer than the proposed duration of your stay (e.g. at least six months after the date of your return journey). You may also need a visa and other documents. Depending on the country, you can under certain circumstances still enter a country using a passport or ID card that has expired. Read the entry requirements for your destination carefully.