Calculator guide
How to use the Savings Growth Planner
Explore how starting savings, monthly contributions, time and a modeled return combine over time.
01Set inputsChoose values, units and assumptions.
02Apply the modelEach month: balance = previous balance × (1 + monthly rate) + monthly contribution.
03Read the resultCheck the output against the assumptions before using it.
What this calculator does
The planner simulates the account month by month and separates starting money, new contributions and modeled growth so the effect of time is visible.
Formula & method
Each month: balance = previous balance × (1 + monthly rate) + monthly contribution.
Assumptions & notes
- The return is a scenario assumption, not a guarantee.
- Monthly contributions are modeled at the end of each month.
- Taxes, fees and account-specific rules are not included.
