13th month salary in Switzerland: entitlement, calculation and pro rata pay
A monthly salary of CHF 5,000 paid 13 times amounts to CHF 65,000 gross a year. But what happens if you start in April, reduce your working hours or leave before December? Understanding the calculation starts with knowing what the 13th month salary pays for and when you are entitled to it.
By Sarah Prieur · Swiss certified public accountant
The key idea
A 13th month salary is not mandatory for every employee in Switzerland. It becomes payable when the employment contract or the rules governing the job provide for it. Where it equals one additional month of salary, it generally builds up over the year, even if it is paid in a single instalment.
At CHF 5,000 a month, each month that counts towards the entitlement therefore adds CHF 5,000 ÷ 12, or approximately CHF 416.67 gross. This explains both pro rata calculations and the balance payable when someone leaves.
Is a 13th month salary mandatory in Switzerland?
In the private sector, Swiss law does not automatically give every employee a 13th month salary. An employer must, however, honour an entitlement it has granted. The first question is therefore: which agreement or commitment provides for this payment?
Start with the employment contract and any staff policies it incorporates. Then check whether a collective employment agreement applies. Known as a CCT in French or a GAV in German, it sets employment terms for an industry or a business. A standard employment contract, issued by a public authority for certain types of work, may also contain relevant provisions.
For example, if the contract states “CHF 5,000 gross per month, paid 13 times a year”, the 13th payment forms part of the agreed remuneration. A poor trading year does not, by itself, allow the employer to withhold it.
An obligation can also arise from established practice. Repeated payments, and any reservations attached to them, must therefore be considered in context. The absence of a clause expressly headed “13th month salary” does not always mean that no entitlement exists.
13th month salary or bonus: why the distinction matters
People sometimes call a 13th month salary a “year-end bonus”. In legal terms, however, agreed salary and a discretionary special payment do not follow the same rules. What matters is what was promised, not just the label on the payslip.
A genuine 13th month salary is part of remuneration, with an amount fixed or calculable under the agreement. A special payment classed as a gratification under Swiss law leaves the employer some discretion, for example over the amount. Such a payment can still become an obligation because of commitments made: not every bonus is optional.
| Question | Genuine 13th month salary | Special bonus (gratification) |
|---|---|---|
| Can the employer freely cancel it? | No, if it is salary due under the agreement. | The employer’s commitment and the payment conditions must be examined. |
| What happens when the employee leaves? | The salary already earned is generally payable. | Under Article 322d of the Code of Obligations, a proportionate payment is due if this has been agreed. |
Read the clause before calculating a final balance or refusing a payment. This is especially important where the contract uses “bonus”, “gratification” and “13th month salary” interchangeably.
How do you calculate a pro rata 13th month salary?
Take the usual example: the contract provides for a 13th month salary equal to one month’s pay for a full year. The monthly salary stays the same, and no absence reduces the entitlement. The calculation is:
Gross 13th month salary = gross monthly salary × number of qualifying months ÷ 12.
Why divide by 12? Because the additional month’s pay builds up across the 12 months of the year. An employee who starts on 1 April and stays until 31 December qualifies for nine months out of 12, or three quarters of the full annual entitlement.
| Situation | Calculation | Gross 13th month salary |
|---|---|---|
| Full year | 5,000 × 12 ÷ 12 | CHF 5,000 |
| Starting on 1 April | 5,000 × 9 ÷ 12 | CHF 3,750 |
| Leaving on 30 June after joining in an earlier year | 5,000 × 6 ÷ 12 | CHF 2,500 |
If employment starts or ends partway through a month, the relevant part of that month must also be calculated. Use the method required by the contract or collective agreement and apply it consistently in payroll.
Where does the 8.33% rate come from?
Dividing an amount by 12 is the same as taking 8.333…% of it. You can therefore add up the qualifying base salaries for the period and divide that total by 12. The displayed rate of 8.33% is rounded, so an adjustment may be needed to reach the correct annual total.
Be careful about the starting amount: use the qualifying salary before adding the 13th month salary itself. With 12 monthly payments of CHF 5,000, the calculation is CHF 60,000 ÷ 12 = CHF 5,000.
What if the annual salary already includes the 13th payment?
An annual salary of CHF 65,000, including a 13th month salary and paid in 13 equal instalments, means 13 payments of CHF 5,000. You do not add another CHF 5,000 to that total. When comparing job offers, look at the total annual salary first, then how it is paid throughout the year.
Part-time work or a pay rise: adjusting the calculation
For part-time work, use the employee’s actual salary
If a job pays CHF 5,000 at full time and the employee works at 80%, their monthly salary is CHF 4,000. With an entitlement to one additional month’s pay and a full year at that level, the 13th month salary is therefore CHF 4,000 gross. The salary already reflects the reduced hours. Applying 80% again would incorrectly reduce the entitlement a second time.
If pay changes, calculate each period separately
Now suppose the monthly salary rises from CHF 5,000 to CHF 5,500 on 1 July. If the entitlement is one twelfth of the year’s base salaries, the first six months and the last six months contribute different amounts:
(6 × 5,000 + 6 × 5,500) ÷ 12 = CHF 5,250 gross.
The same reasoning applies when working hours change. A reduction from CHF 5,000 to CHF 4,000 halfway through the year would produce a 13th month salary of CHF 4,500 under this method. Do not automatically use December’s salary: first check whether the contract or collective agreement requires this calculation or a different basis.
For hourly or variable pay, check which earnings count
Commissions, bonuses and overtime are not necessarily treated in the same way as base salary. Identify which components qualify under the applicable rules. For example, the Swiss hospitality collective agreement sets out its own calculation rules in Article 12. Those rules apply within that agreement’s scope and cannot be assumed to cover every Swiss business.
When is it paid, and what happens when you leave?
Payment often takes place in November or December, but there is no single payment date for every job in Switzerland. The contract or collective agreement may provide for an annual payment, two instalments or an amount paid each month. The relevant amount should be clearly identified on the payslip.
The payment date and the period over which salary is earned are two different things. An employee who resigns in June does not automatically lose six months of accrued 13th month salary simply because the usual payment date is in December.
When employment ends, calculate the entitlement up to the end of the employment relationship and deduct any instalments already paid. For example, a salary of CHF 5,000 from January to September produces an entitlement of CHF 3,750. If CHF 2,500 was paid in June, the final payslip should include the remaining CHF 1,250 gross.
For a genuine salary component, a simple requirement to remain employed on 31 December cannot remove salary already earned. A special bonus may be subject to different conditions, as explained above. Any relevant industry rules should also be checked.
Does time off reduce the 13th month salary?
This depends on the type of absence and the pay maintained during it. Ordinary paid annual leave does not, by itself, reduce a monthly paid employee’s 13th month salary.
Unpaid leave can reduce the period or earnings used in the calculation. If one full month generates no entitlement, a salary of CHF 5,000 in each of the other 11 months produces, under the usual formula, CHF 5,000 × 11 ÷ 12 = CHF 4,583.33 gross.
For sickness or an accident, look at how income is covered. Does the employer continue paying salary, or does an insurer pay daily benefits? These benefits replace some or all of the income lost during an inability to work. Their calculation may already include a share of the 13th month salary.
The employment contract, salary continuation rules and insurer’s statement must therefore be checked together. Automatically reducing the 13th month salary for every day off could remove pay the employee is entitled to. Adding an amount already covered by insurance could instead result in double counting.
From gross pay to the employer’s actual cost
The amounts calculated in this article are gross. Employees receive net pay after the applicable deductions. A 13th month salary generally forms part of the salary subject to social security contributions and of taxable income. Payroll must account for insurance ceilings and, where applicable, withholding tax rules. For the Geneva rules, our article on withholding tax in Geneva explains how the deduction from salary works.
The employer’s cost also exceeds the gross amount because employer contributions must be added. Our article on social security contributions in Switzerland explains the different deductions and charges.
Plan for both the expense and the cash payment
A business with five employees each earning CHF 5,000 a month and entitled to a full 13th month salary needs to fund an additional CHF 25,000 gross, plus employer contributions. Spreading that expense through the accounts means recognising approximately CHF 2,083.33 each month for the five employees, before employer contributions.
This gives a more accurate picture of profit throughout the year. It does not, however, put cash aside. The payment must also be included in the cash flow budget, especially if all 13th month salaries are paid in the same month.
My advice
Track three separate figures for each employee: the 13th month salary earned since January, instalments already paid and the balance still due. After a pay rise, a long absence or a change in working hours, comparing these figures helps catch a discrepancy before the year-end payslip.
Conclusion: establish the entitlement, then calculate the amount
To calculate a 13th month salary correctly, first check what the employment contract and applicable rules provide for. Next, identify the earnings and period that qualify, then deduct any instalments already paid.
When salary and working hours stay the same, the pro rata calculation is straightforward. Problems usually arise when the formula is applied without checking what changed during the year. A clear statement showing the calculation basis, qualifying period and previous payments helps both the employer preparing payroll and the employee reading it.
Related articles
- Employment contracts in Switzerland
- Swiss salaries: median pay and salary benchmarks
- Social security contributions in Switzerland
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Talk to Karpeo →Frequently asked questions
Is a 13th month salary mandatory everywhere in Switzerland?
No. In the private sector, check the employment contract, any applicable collective or standard employment contract, and the employer’s commitments. Once agreed as a salary component, the 13th month salary must be paid under the applicable rules.
How do you calculate a 13th month salary for nine months?
If the annual entitlement equals one month’s salary and pay stays constant, multiply the monthly salary by nine and divide by 12. At CHF 5,000 a month, this gives CHF 3,750 gross before deducting any instalments already paid.
Do you lose your 13th month salary if you resign?
No, not where it is a genuine salary component already earned. The amount due up to the end of employment is generally payable after deducting previous instalments. A special bonus may be subject to different conditions.
Can a 13th month salary be paid monthly?
Yes, if the contract and applicable rules allow it. Where the entitlement is one twelfth of the salary basis, the monthly amount is approximately 8.33% of that basis, excluding the 13th month salary itself. It should be clearly identified, with rounding adjusted where necessary.
Does an employee working at 80% receive a full 13th month salary?
If the contract provides for an additional month’s pay for a full year, the payment equals one month of the employee’s salary at 80%. With actual monthly pay of CHF 4,000 throughout the year, the 13th month salary is CHF 4,000 gross.
Is a 13th month salary exempt from tax or social security contributions?
No. A 13th month salary generally forms part of the salary subject to social security contributions and of taxable income. Net pay depends on the deductions and tax rules applicable to the employee.
Official sources and references
Sources checked on 29 September 2026. The numerical examples illustrate the assumptions stated in the article; individual and industry rules may differ.
- Swiss Code of Obligations — salary, special bonuses and salary continuation (Articles 322, 322d and 324a; French text)
- Swiss hospitality collective agreement — Article 12, 13th month salary (French text)
- AHV/IV Information Centre — employee and employer social insurance contributions (French factsheet)
- AHV/IV Information Centre — unemployment insurance contributions (French factsheet)
About the author
Sarah Prieur
Sarah Prieur is a Swiss certified public accountant, partner and head of operations at Karpeo. She supports SMEs, self-employed professionals and entrepreneurs with accounting and tax, and oversees the quality of client work. Before Karpeo, she spent eight years in audit at PwC Switzerland, progressing to manager.
Read more about Sarah →