About 694 €/month, every month, for eighteen years.
The shape of 18 years
A child is not one expense. It is a curve.
Monthly outflow per year of the child's age. Direct cash in cyan; childcare in violet, concentrated in the first years. The teen years rise quietly but never spike like the early ones.
Direct cashSource: HCFEA - Rapport coût de l'enfant (synthèse ONPES 2014–2015 / valorisation CREDOC)
What it could have been
The same money, invested instead.
If you set aside 694 €/month in a globally diversified portfolio at a 6% real return, after 18 years you would hold roughly:
268 651 €
At 6% real return · 149 808 € contributed, 118 843 € from compounding
About 1.8× the direct cost.
This is the opportunity cost in plain numbers. It is not an argument against children. It is the size of the choice you are making, so you can plan around it: a savings goal, an 18-year compounding account in the child's name, or simply a clearer head.
For scale
What else costs about 149 808 €?
A down payment on a home · 80 000 €1.9×
A luxury car · 95 000 €1.6×
Seed capital for a small business · 200 000 €0.7×
Ten years of rent in a major city · 200 000 €0.7×
A full K-12 private school education · 250 000 €0.6×
See all scenarios at once
1 child
149 808 €
149 808 €
2 children
299 616 €
299 616 €
3 children
449 424 €
449 424 €
Partner spotlight · True WealthPartner link
Open an account in the child's name.
Setting aside 10% of the child's costs is 69 €/month. Open an account in the child's name and turn the 18-year horizon into the longest compounding window you'll ever have. True Wealth invests it on autopilot: globally diversified ETFs, automatic rebalancing, no stock picks.