Investment Return Calculator
Project the future value of any investment portfolio. See how an initial lump sum and monthly contributions compound over time.
How it works
- 1Enter your starting balance
Whatever you already have invested today (or $0 to start fresh).
- 2Add a monthly contribution
Use what you can realistically invest every month.
- 3Choose an expected return
7% is a reasonable long-term US stock market estimate after inflation.
Investment returns are the engine of long-term wealth. Unlike savings accounts that earn 4–5%, broadly diversified stock portfolios have historically returned 7–10% per year over multi-decade periods — though with significant year-to-year volatility.
The most important factor in long-term investing isn't the rate of return — it's time. A $500/month investment at 7% return becomes about $87,000 after 10 years, $263,000 after 20 years, and a stunning $610,000 after 30 years. That's the magic of compound returns.
Use this calculator to test assumptions: how much will my Roth IRA be worth at retirement? What if I bump my contribution from $500 to $750/month? What if returns are lower than expected? Running multiple scenarios is the best way to set realistic financial targets.
Remember: real market returns aren't smooth. Plan for years with -20% returns and years with +30% returns. Stay invested through the dips — historically that's been the most reliable way to capture long-term growth.
Example scenarios
Grows to ~$610,000. You contributed $180,000 — the rest is investment growth.
Grows to ~$810,000. Strong path to retirement security.
Grows to ~$1,100,000. Time + compounding does most of the work.
Common questions
What return rate should I use?
The S&P 500 has averaged about 7% annual return after inflation over the long run (10% nominal). For a conservative projection use 5–6%; for an optimistic one use 8–10%. Never assume past returns are guaranteed.
Do these calculations account for inflation?
Use a 'real' return rate (e.g. 5–7%) to express results in today's dollars. Use a nominal rate (e.g. 8–10%) to see the future-dollar value, which will buy less than today.
What's the difference between this and a compound interest calculator?
They use the same math. 'Investment return' framing emphasizes long-term growth of stocks/ETFs, while 'compound interest' framing emphasizes savings accounts and bonds. Same formula either way.
Should I include taxes?
Tax-advantaged accounts like 401(k)s and IRAs grow tax-deferred or tax-free. For taxable brokerage accounts, dividends and realized gains are taxed yearly — subtract ~0.5–1% from the assumed return as a rough tax drag.