Debt versus investing decision tool

Build two scenarios side by side to understand when overpaying a mortgage beats investing spare cash – and when capital markets deliver higher wealth.

See the impact in PLN terms

  • ★ Parallel timelines – simulate overpayments and investments month by month for up to 30 years.
  • ★ Break-even return – find the net rate of return required to outperform debt repayment.
  • ★ Inflation-aware results – view real purchasing power after CPI adjustments.
  • ★ Belka tax ready – all investment results include the 19% capital gains tax used in Poland.

Example scenarios

Monthly overpayment 1 000 PLN

Break-even 6.1%

With a 5.7% loan rate, investing needs to earn at least 6.1% net each year to pull ahead.

ETF scenario

15-year horizon

An 8% net return builds 64k PLN more wealth than pure overpayments – assuming disciplined investing.

Safety buffer

6-month reserve

The calculator recommends filling an emergency fund before redirecting all cash into investing.

Model your own scenario Use the lightning version