Monthly deposit calculator
Compound Interest Calculator With Monthly Contributions
Calculate how a starting balance and regular monthly deposits may grow over time. This page is built for people who save or invest every month, not just once.
Estimated final balance
$ —
Total contributed
$ —Compound growth
$ —Monthly contribution example
| Starting amount | Monthly deposit | Return | Years | Approx final value |
|---|---|---|---|---|
| $5,000 | $300 | 7% | 20 | About $174,000 |
| $0 | $100 | 7% | 10 | About $17,300 |
| $10,000 | $500 | 6% | 25 | About $384,000 |
Why monthly deposits need different math
A lump-sum formula assumes the whole principal grows for the full period. Monthly deposits arrive gradually, so each deposit compounds for a different amount of time. That is why this page uses period-by-period projection logic.
Related pages
FAQ
How do monthly contributions compound?
Each deposit begins compounding after it is added. Earlier deposits grow longer than later ones.
Should I use beginning or end of month?
Beginning of month gives deposits slightly more time to grow. End of month is more conservative.
Does this include fees?
No. Lower the return assumption manually if you want to account for fees or tax.