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Duodécimos Calculator

Receiving the holiday (férias) and Christmas (Natal) bonuses "em duodécimos" means getting them split across the 12 months of the year, added to each salary, instead of as two lump sums. Enter your monthly base salary and the duodécimos percentage (0%, 50% or 100%) to see your monthly pay in each option. The key point: the annual total is exactly the same, and duodécimos change when you receive the money, not how much.

Enter your gross monthly base salary and the percentage of each bonus (holiday and Christmas) you receive in duodécimos. Figures are gross, before Social Security and IRS.

Gross monthly pay
€1,750.00
Includes €250.00 of duodécimos per month
Gross total over the year
€21,000.00
Always 14 salaries. The same in every option; only the spread across the months changes.
OptionMonthly payLump-sum bonusesAnnual total
0% in duodécimos€1,500.00€3,000.00€21,000.00
50% in duodécimos€1,625.00€1,500.00€21,000.00
100% in duodécimos€1,750.00€0.00€21,000.00

'Lump-sum bonuses' is the part of the two bonuses paid as single payments (holiday before the holidays, Christmas by 15 December).

Gross figures. Social Security (11%) and IRS apply to the same annual total in every option; only the month-to-month withholding can vary, reconciled in the IRS return.

Educational estimate, not tax or financial advice. It shows the gross distribution of the holiday and Christmas bonuses in duodécimos. Duodécimos require an agreement with your employer.

What duodécimos are

In Portugal you earn 14 "salaries" a year: 12 monthly salaries plus the holiday and Christmas bonuses, each equal to one month of pay. By default each bonus is paid in full (Christmas by 15 December, holiday before the holidays). In duodécimos you receive a twelfth of each bonus (the bonus divided by 12) added to every monthly salary. It needs a written agreement with your employer.

How the monthly duodécimo is worked out

Each bonus is one month of salary, so a twelfth of a bonus is your salary divided by 12. With both bonuses fully in duodécimos you add two twelfths a month (holiday ÷ 12 + Christmas ÷ 12), i.e. salary × 2 ÷ 12. On a €1,500 salary that is €250 extra a month (€125 + €125), so monthly pay rises from €1,500 to €1,750. At 50% you receive half in duodécimos and the other half as a single payment.

The annual total is always the same

This is the part most people get wrong: duodécimos do not make you receive more or less over the year. You always receive 14 salaries. At 0% you get the monthly salary plus both full bonuses in June and December; at 100% you get a higher monthly pay and forgo those two large payments. The annual sum is identical in all three options. The difference is purely cash-flow: higher, steadier monthly pay, or two big top-ups mid-year and at year-end.

What about net pay and IRS?

This calculator shows gross figures. Social Security (11%) and IRS apply to the same annual total whichever option you pick, so the annual net does not change either. What can change is the month-to-month withholding: a bonus paid in full is withheld on its own, while a duodécimo is added to the month’s salary and can fall in a higher withholding band. That is reconciled in the annual return. For the IRS side, see the withholding and IRS refund calculators.

Worked example

On a base salary of €1,500 a month you receive €21,000 a year (14 × €1,500) in every option. At 0% in duodécimos you get €1,500 a month plus two full €1,500 bonuses (in June and December). At 50% you get €1,625 a month (€125 more) plus €750 of each bonus as a single payment. At 100% you get €1,750 a month (€250 more) and no large bonus payments. In all three cases the yearly total is €21,000.

Frequently asked questions

What are duodécimos?
It is receiving the holiday and Christmas bonuses split across the 12 months of the year, added to each salary, instead of two lump sums. Each bonus is one month of salary, so a twelfth is the bonus divided by 12. It needs a written agreement with your employer.
Do I receive more money in duodécimos?
No. The total you receive over the year is exactly the same, 14 salaries, whether paid in full or in duodécimos. Duodécimos only change the distribution: higher, steadier monthly pay, in exchange for giving up the two large bonus payments in June and December.
How is the duodécimos amount calculated?
Each bonus is one month of salary, so a twelfth is your salary divided by 12. With both bonuses fully in duodécimos you add salary × 2 ÷ 12 each month. On a €1,500 salary that is €250 a month (€125 from each bonus); at 50% it is €125 a month.
Can I choose 50% or 100% in duodécimos?
Yes. The usual options are 0% (the full bonus), 50% (half in duodécimos, half as a single payment) or 100% (the whole bonus in duodécimos). It can apply to one bonus, to both, or be mixed. A written agreement with your employer is always required.
Do duodécimos change IRS and Social Security?
Over the year, no: Social Security (11%) and IRS apply to the same amount. What can change is the month-to-month withholding: a full bonus is withheld on its own, while a duodécimo added to the salary can fall in a higher withholding band. The difference is reconciled in the annual IRS return.
When do I receive the bonuses if I do not choose duodécimos?
By default the Christmas bonus is paid by 15 December and the holiday bonus before the holiday period. In duodécimos those amounts arrive spread across every month. The choice comes down to preferring higher, steadier monthly income or two larger top-ups during the year.

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Author: Thorben Rasmus Idel · Reviewed by: Nahar Geva · Last reviewed: 2026-06-07