Having dependent children doesn't just affect your day-to-day life: it also directly reduces the income tax withholding applied to your payslip every month. Many workers fail to correctly report this circumstance to their employer and end up with a higher withholding rate than they should actually have.
The minimum allowance for dependents: the key piece
Spain's income tax system recognizes a "minimum allowance for dependents," an amount subtracted from your taxable base before the tax is calculated, based on the number of children you have. The more children you have, the higher this allowance, and the amounts aren't linear: they increase progressively from the second child onward, with a bigger marginal reduction the more children there are.
Why it matters to report this to your employer
The income tax withholding your employer applies to your payslip is calculated, in part, from the information you yourself declare on Form 145 (the notice of personal data to the payer). If you don't correctly report your number of children, your employer will apply a withholding rate calculated without that reduction, which means you'll overpay month after month, even though that excess eventually gets settled when you file your annual tax return.
The effect is an adjustment, not a guaranteed extra refund
It's important to understand that correctly declaring your children doesn't make you "earn money": it simply adjusts your monthly withholding so it more closely matches the actual income tax you owe based on your family situation, avoiding a situation where you advance more money than necessary throughout the year, only to wait for it to be refunded when you file your return.
Other family factors that also play a role
Besides the number of children, there are other minimum allowances and reductions tied to your family situation that also affect withholding:
- Spousal minimum allowance in certain joint taxation situations.
- Disability minimum allowance, whether it's your own or that of dependent children or parents.
- Large family status, which in some regions grants access to additional specific deductions.
When to update your notice to your employer
It's advisable to update Form 145 whenever your family situation changes (the birth of a child, a change in custody arrangements, a change in a recognized degree of disability), since withholding doesn't adjust automatically without that explicit notice from you.
Simulate the effect on your withholding
Our income tax calculator lets you enter your number of children and see how it affects your effective withholding rate and your estimated net annual salary.