DCA calculator
Invest a fixed amount every month into the S&P 500, gold, Bitcoin, Ethereum or Treasury bonds and see the result with real prices: total invested, final value, yearly return and the worst dip you would have bought through.
Market data through Sep 2026, updated monthly. How we calculate$100 a month into the S&P 500 since Jan 2015 is worth
You would have put in $14,100 over 141 monthly buys. At the worst point, around Mar 2020, the balance was down 18% from its high, and the plan kept buying.
If you had invested the whole $14,100 in Jan 2015, it would be worth $64,623. S&P 500 monthly average prices, dividends reinvested (recent months use the last reported dividend, Jun 2023). Data through Sep 2026. One buy per month at that month's average price; no fees or taxes. Past returns do not predict future returns.
How this calculator works
Pick an amount, an asset and a start date. The calculator buys at each month's average price, reinvests S&P 500 dividends if you choose, and values the result at the latest available month.
It shows the worst drop you would have lived through and compares the result with investing the same total all at once.
Common questions
What is dollar-cost averaging?
Investing the same amount on a fixed schedule regardless of price, so you buy more shares when prices are low.
Is DCA better than investing a lump sum?
Historically a lump sum has won about two-thirds of the time, because markets rise more often than they fall. But most people invest from a paycheck, which is DCA by nature.
Why monthly average prices?
They are the longest free, consistent record of the S&P 500. Real buys on a given day would land a little above or below.
FatDCA calculators are educational estimates, not investment, tax or legal advice. Results depend on the assumptions you enter, and past returns do not predict future returns.
One small deposit a week, for your brain
- 1chart from real data
- 1idea in plain English
- 1thing to do this week