About £1,162/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: Child Poverty Action Group - The Cost of a Child in 2025 (October 2025)
What it could have been
The same money, invested instead.
If you set aside £1,162/month in a globally diversified portfolio at a 6% real return, after 18 years you would hold roughly:
£450,104
At 6% real return · £250,992 contributed, £199,112 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 £250,992?
Seed capital for a small business · £200,0001.3×
Ten years of rent in a major city · £250,0001.0×
A city apartment · £300,0000.8×
A full K-12 private school education · £350,0000.7×
An established small business · £400,0000.6×
See all scenarios at once
1 child
£250,992
£250,992
2 children
£574,560
£574,560
3 children
£0
Partner spotlight · True WealthPartner link
Open an account in the child's name.
Setting aside 10% of the child's costs is £116/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.