When a child turns 18, child benefit and other child-related payments stop. At the same time, new costs arise for health insurance and education, Nibud said. If 18-year-olds have an income, that can also impact on how much social security and supplementary benefits their parents are entitled to.

Many parents, Nibud says, are reluctant to ask their children to contribute to the household budget, particularly if they are still studying.

But if young people are expected to help cover household costs, it becomes more difficult for them to save or move out and live on their own. That can delay independence and further widen differences and opportunities between young adults, Nibud director Mattias Gijsbertse said.

With young adults now leaving home at an average age of 24, Nibud said the sharp income drop raises the question of whether the transition at 18 should be softened. The agency is also calling for better preparation not only for young people but also for their parents to cope with the financial changes.