What does this assume?
Terra converts the annual return assumption into an equivalent monthly rate, applies growth monthly, and adds the contribution at the end of each month.
Free Financial Calculator
Compound Interest Calculator
See how a starting balance and regular monthly contributions could compound over time under an annual return assumption you choose.
Reviewed · Aug 16, 2026
What this does
Shows how a starting balance plus regular contributions could grow under a return assumption you choose.
Have ready
Your starting amount, monthly contribution, expected annual return and time horizon.
Terra approachTransparent assumptionsEducational comparisonNo product recommendationHow Terra handles revenue →
Your assumptions
Change the numbers yourself. Terra shows a deterministic scenario, not a prediction.
7% means a 7% full-year return in this model. Terra converts that effective annual return to an equivalent monthly rate because contributions are modeled monthly.
Saved scenarios stay privately in this browser under My Terra. Nothing is saved unless you choose Save this scenario.
How to read it
Useful math, with visible limits.
Is the return guaranteed?
No. The return is a user-entered illustration. Real investment returns vary and can be negative.
Why open the graph or table?
The headline shows the destination. The graph shows compounding visually; the table separates your contributed dollars from modeled growth each year.
Terra calculators are educational scenario tools. Results depend on the assumptions entered and do not predict returns, taxes, employer plan rules, advisor value, or future financial outcomes.