Compound Interest Calculator

Investment Calculator

A brokerage account or retirement-style investment compounds over time just like a savings account — usually at a higher expected return. Enter your starting balance, your realistic expected annual return, your time horizon, and how much you plan to add each month to see your projected portfolio value.

Final balance
$784,388
Total interest
$599,388
Total contributions
$185,000
ContributionsInterest

Year-by-year breakdown

PeriodContributionsInterestBalance
Year 1$11,000$880$11,880
Year 2$17,000$2,310$19,310
Year 3$23,000$4,335$27,335
Year 4$29,000$7,002$36,002
Year 5$35,000$10,362$45,362
Year 6$41,000$14,471$55,471
Year 7$47,000$19,389$66,389
Year 8$53,000$25,180$78,180
Year 9$59,000$31,914$90,914
Year 10$65,000$39,668$104,668
Year 11$71,000$48,521$119,521
Year 12$77,000$58,563$135,563
Year 13$83,000$69,888$152,888
Year 14$89,000$82,599$171,599
Year 15$95,000$96,807$191,807
Year 16$101,000$112,631$213,631
Year 17$107,000$130,202$237,202
Year 18$113,000$149,658$262,658
Year 19$119,000$171,150$290,150
Year 20$125,000$194,842$319,842
Year 21$131,000$220,910$351,910
Year 22$137,000$249,542$386,542
Year 23$143,000$280,946$423,946
Year 24$149,000$315,342$464,342
Year 25$155,000$352,969$507,969
Year 26$161,000$394,086$555,086
Year 27$167,000$438,973$605,973
Year 28$173,000$487,931$660,931
Year 29$179,000$541,286$720,286
Year 30$185,000$599,388$784,388
Compare High-Yield Savings Rates →

Why investment returns compound more aggressively

Equity and broad-market index investments historically deliver higher long-run returns than cash savings — but with that higher expected return comes volatility. This calculator uses a deterministic average annual return; it cannot predict market crashes, sequence-of-returns risk, or years when your portfolio shrinks. Use it as a long-horizon planning aid, not a guarantee.

Because investment returns are often quoted annually, the default compounding here is annual rather than monthly. The engine underneath is the same as the savings and retirement calculators on this site — only the defaults and framing differ.