Retirement & investing · free calculator
Compound interest with monthly contributions
Future value of a starting balance plus recurring monthly contributions at a configurable APY — the single calc that motivates most early retirement plans.
Projected ending balance
$540,882 from compounding
Total contributions
$243,408 added after the starting balance
Show the work
- Investment horizon360 months
- Final monthly contribution$906
- Starting balance only$76,123
- Growth minus contributions$540,882
Contributions change the compounding story
Compound interest on a starting balance is powerful, but recurring contributions usually do most of the work in the early years.
This calculator separates:
- Starting balance
- New contributions
- Growth from compounding
- Contribution increases over time
That split matters because a large ending balance can come from different behaviors. Some plans need a higher return assumption. Others simply need a higher monthly contribution or a longer runway.
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