Compound interest calculator
Enter your starting amount, monthly contribution, expected annual return, and time horizon. The result shows your projected portfolio value at the end of the period.
Projected portfolio value
$685,479
Total contributed
$130,000
Interest earned
$555,479
Based on $10,000 starting + $500/month at 10% annual return over 20 years.
How it works
FV = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) − 1) / (r/n)]
Where P = principal, r = annual rate (decimal), n = compounding periods per year (12 for monthly), t = years, PMT = monthly contribution.