Kalkulator inwestycji
The detailed guide below is currently available in English.
The engine behind the projection
The simulation grows your balance every month at g = (1 + annual return)1/12 − 1, the geometric monthly equivalent of the annual rate, and adds each contribution at the start or end of the period you choose. Compounding monthly at the geometric rate is slightly more accurate than the common approximation of dividing the annual rate by 12.
Contributions made at the beginning of each period earn one extra period of growth, which is why the "beginning" option produces a higher ending balance.
Making the most of compounding
- Time in the market matters more than the starting amount: growth on growth dominates late in the table.
- Increasing contributions beats chasing an extra point of return for most savers — test both scenarios.
- Remember taxes and fund fees. A 1% fee is effectively a 1% lower return, and the yearly table shows what that costs over decades.
Częste pytania
Is the expected return guaranteed?
No. It is a smooth average used for planning. Real portfolios move in bursts of gains and losses, and the order of those returns affects outcomes, especially near the time you withdraw.
Should contributions go in at the beginning or end of the month?
Match your reality. If you invest on payday, "beginning" is closer to the truth; if you transfer whatever is left at month-end, choose "end".
Does this account for inflation?
The projection is in nominal dollars. To think in today’s purchasing power, subtract expected inflation from your return — or compare results in the inflation calculator.