If you only employ one person marginally with a salary of up to € 551.10 per month in 2025, no additional costs are incurred.
However, a tax (employer's contribution) is due if
you have more than one marginally employed person and
the monthly payroll (excluding special payments) of all marginally employed persons exceeds 1.5 times the marginal earnings threshold (example for 2025: € 551.10 x 1.5 = € 826.65).
If the childminder is self-employed, you will not have to pay tax.