Researched by ExpatMoneyEU Research Team · Last updated 13 November 2026 · Data: French 13th month (treizième mois) — not statutory; due only where a contract, collective agreement, custom or employer commitment provides for it (service-public.fr, fiche F2301); employee social charges estimated at 22% of gross — 2026. Estimate only — not tax or financial advice. This calculator assumes a 13th month applies to you — check your contract first, because France has no legal right to one without a contractual source.
ExpatMoneyEU verdict: On a €2,800 monthly gross salary with a full year worked, your French 13th-month salary is €2,800 gross — taking your annual pay from €33,600 to €36,400. Estimated employee social charges at 22% are about €616, leaving about €2,184 net after social charges, before income tax. But first check your contract: France has no legal right to a 13th month unless your contract, collective agreement or company practice provides one.
13th-month gross = monthly gross salary × months worked ÷ 12. Employee social charges are estimated at 22% of the gross bonus — the real rate is usually 20–23% of gross for a private-sector employee and varies with your status and collective agreement, so treat this as an estimate. Income tax (prélèvement à la source) is deducted separately, so the net shown is after social charges but before income tax. The 13th month is not a legal right in France: it is only due if your employment contract, collective agreement, company custom or employer commitment provides for it.
What is the 13th-month salary in France?
The 13th-month salary — the treizième mois — is one extra month's gross pay on top of your 12 monthly salaries, usually paid in December, just before the holidays. For an expat in Paris, Lyon or Marseille it can be the biggest single payment of the year. But there is one fact every expat in France must understand first: the 13th month is not a legal right. French law does not require any employer to pay one. It is only due if your employment contract, your collective agreement (convention collective), a long-standing company custom or a written employer commitment provides for it. If none of those sources says you get a 13th month, you do not have one — and this calculator assumes one applies to you, so check your contract before you count on the money.
When it does apply, the amount is usually one month's gross salary, and the payment timing varies: most employers pay the whole bonus in December, some split it into two halves in June and December, and a few spread it across the year in monthly or quarterly instalments. Collective agreements cover about 98% of French employees, so many expats are covered through their sector's agreement even if their individual contract says nothing — the agreement is often where the 13th month lives. Some agreements also set conditions, such as a minimum length of service, or exclude certain categories of staff, so the exact rules for your job are in your agreement, not in the law.
→ Free France Net Salary Calculator: Gross to Net — your take-home after French tax and social charges
How to use it (4 steps)
- Enter your monthly gross salary in euros — the figure on your contract before tax and social charges.
- Enter how many months you worked in France this year, from 1 to 12. If you started mid-year, the bonus is pro-rata.
- Choose your payment timing: a December lump sum, or split in two (June + December) — the calculator shows each instalment when you split it.
- Read your 13th-month gross, the estimated employee social charges (22%) and your estimated net — then check your contract or collective agreement to confirm the bonus actually applies to you.
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The formula, with every variable explained
13th-month gross = monthly gross salary × months worked ÷ 12. It is one month's pay for a full year worked, pro-rata if you started mid-year. Estimated employee social charges = 13th-month gross × 22%. Estimated net = 13th-month gross − estimated employee social charges. Annual total = (monthly gross × months worked) + 13th-month gross. Your monthly gross salary is your contracted pay before tax and social charges. Months worked is the number of months you were employed in France this year, from 1 to 12. The 22% is an estimate: a private-sector employee in France typically pays about 20–23% of gross in employee social charges — state pension, complementary pension (Agirc-Arrco) and the CSG/CRDS — and the exact rate depends on your status, salary level and collective agreement. The 13th month is treated like normal salary for social charges and income tax: it is fully subject to both, so income tax (prélèvement à la source) is deducted separately on top of the social charges shown here.
Worked example with real numbers
Example: a monthly gross salary of €2,800 with all 12 months worked. The 13th-month gross is €2,800 × 12 ÷ 12 = €2,800. Estimated employee social charges at 22% are €2,800 × 22% = €616, leaving an estimated net of €2,184 after social charges, before income tax. Base pay for the year is €2,800 × 12 = €33,600, so the annual total with the bonus is €36,400 across 13 payments. If the bonus is split in two, each instalment is €1,400 gross and about €1,092 net. Now a mid-year start: €2,800 a month with 6 months worked gives a 13th-month gross of €1,400, charges of €308 and an estimated net of €1,092. And on a €2,000 monthly salary for a full year, the bonus is €2,000 gross, €440 of estimated charges and €1,560 net.
French 13th-month examples for common salaries (2026)
| Monthly gross salary | 13th month (gross) | Est. social charges (22%) | Estimated net | Annual total |
|---|---|---|---|---|
| €1,800 | €1,800 | €396 | €1,404 | €23,400 |
| €2,200 | €2,200 | €484 | €1,716 | €28,600 |
| €2,800 | €2,800 | €616 | €2,184 | €36,400 |
| €3,500 | €3,500 | €770 | €2,730 | €45,500 |
All figures are for a full 12 months worked in 2026. Employee social charges are estimated at 22% of the gross bonus — the real rate is usually 20–23% and varies with your status and collective agreement. The net shown is after social charges but before income tax, which is deducted separately. With fewer months worked, multiply the bonus by months worked ÷ 12. The 13th month only applies if your contract, collective agreement, custom or employer commitment provides for it.
→ Free Portugal 13th & 14th Month Salary Calculator 2026 — compare the Portuguese system
Sources and disclaimer
The French 13th month (treizième mois) is not required by French law: a bonus is due only if an employment contract, a collective agreement (convention collective), a company custom or an employer commitment provides for it — service-public.fr, fiche F2301, "Salaire, primes et avantages". Where it applies, it is usually one month's gross salary, paid in December or split, and it is subject to social security contributions and income tax like normal salary. Employee social charges for a private-sector employee are typically about 20–23% of gross salary (state pension, Agirc-Arrco complementary pension and CSG/CRDS); this calculator uses 22% as a clearly labelled estimate. Estimate only — not tax or financial advice. This calculator assumes a 13th month applies to you and does not deduct income tax; confirm your entitlement, your collective agreement and the exact figure on your payslip or with a qualified adviser before making decisions.
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