For educational purposes only — not financial advice. Learn about our editorial process
Compounding isn't a slogan — it's a function. Set what you have, what you'll add, and how long. The curve tells the rest of the story.
Same contribution, same return. Only the start date changes. This is why the first dollar matters more than the biggest one. Each card shows the ending balance and how it compares to starting now.
Future value with an initial balance plus recurring contributions:
FV = P(1+r)n + PMT × [ (1+r)n − 1 ] / rP = your starting amount · PMT = each monthly deposit · r = the monthly growth rate · n = number of months. We compound monthly here, which is how most index funds pay dividends in practice.
Recommended
Fidelity
Investors who want one platform for nearly every account type
It pairs $0 stock and ETF trades with no account minimum and a wide range of account types, making it a strong all-around home for most investors.
Management fee0%
Vanguard
Long-term, buy-and-hold index fund investors
Its low-cost index funds and long-term, retirement-focused approach suit buy-and-hold investors who care most about keeping fees down.
Management fee0%
Charles Schwab
Investors who want banking and brokerage under one roof
It combines $0 trades and no account minimum with banking integration and the thinkorswim platform, so investing and everyday banking live side by side.
Management fee0%