The maintenance figure is the one in the agreement or the court decision. Household income is that of the home the child lives in, and the law does not divide it by headcount: it uses a scale where the applicant weighs 1, each adult 0.7 and each minor 0.5 (article 5 of Decree-Law 70/2010).

The Fund pays forward and does not pay arrears. Payment starts in the month after the court decision is notified, with no payment of instalments already due (article 4(4) and (5) of Decree-Law 164/99): the months already missing remain the parent's debt. That is the strongest reason not to wait.

What this calculator shows is the MAXIMUM the Fund can pay, not what it will pay: the court sets the amount having regard to the household's economic capacity, the maintenance set and the child's needs, so it may set less. Out of scope: the full means-test income definition, the judicial fixing itself, and the garnishment of the debtor's wage, which has its own calculator. 2026 values (IAS of 537.13 €).

This is an educational estimate and does not constitute legal or financial advice.