13th Month Salary in Switzerland: Definition and Rights

Definition

The 13th month salary represents an extra month's compensation beyond the 12 regular monthly payments, equivalent to roughly 8.33% of annual salary (1/12 of the year). It is not mandated by federal law in all sectors, but it is standard practice in the vast majority of Swiss employers in formal employment relationships.

When Is It Mandatory?

The 13th month salary becomes legally required in three situations: when the applicable collective bargaining agreement (GAV/CCT) explicitly includes it; when the employment contract specifies it; or when the employer has paid it repeatedly without reservation for several years, creating an implied right. Without a GAV provision, contract clause, or established practice, the 13th month remains discretionary.

Calculation and Payment Timing

The 13th month is calculated on base salary, excluding overtime and variable bonuses. For employees who join or leave mid-year, it is prorated by months worked. Payment typically occurs in December; some employers split it (June and December) per contract or GAV schedule.

Social Contributions

The 13th month salary is subject to the same social security contributions as regular salary: AHV, BVG, ALV, etc. It appears on the annual wage certificate (Lohnausweis) and is taxable income. For employees subject to withholding tax (Quellensteuer), the 13th month inflates the payment month's taxable base, potentially triggering a higher marginal rate for that month.

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Frequently Asked Questions

Is the 13th month salary mandatory in Switzerland?

Not universally. It is mandatory when required by a GAV, employment contract, or implied by long-standing employer practice. In practice, the vast majority of Swiss employers pay it.

When is the 13th month salary paid?

Typically in December, sometimes in two tranches (June and December). The exact date is governed by your contract or applicable GAV.

How is the 13th month prorated for part-time or mid-year employees?

It is prorated based on employment percentage and months worked. A 50% employee earns 50% of a full 13th month; an employee who worked 6 months earns 6/12 of a full 13th month.

Can an employer unilaterally cancel a 13th month that has been paid for several years?

No, not unilaterally. After an employer has paid a 13th month salary regularly and without reservation for 3 or more consecutive years, it becomes an implied contractual right (gewohnheitsrechtlicher Anspruch) under Swiss case law. The employer cannot simply stop paying it, stopping requires either employee consent or a formal modification notice (Änderungskündigung), meaning the employer must terminate the contract and offer new terms without the 13th month. An unilateral cessation can be challenged at the labour court.