Dollar-Cost Averaging Calculator

Dollar-cost averaging means investing a fixed amount on a regular schedule instead of all at once. Enter a monthly amount and a period, and this tool backtests it against the real history of the S&P 500 (dividends reinvested) — showing the final value, what you put in, your annual return, and how it compares to investing the same total as a lump sum.

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Final value —
Total invested —
Total return —
Average per year —

Assumes dividends are reinvested (total return) and contributions at the start of each month. Monthly S&P 500 index 1950–2025: intra-year shape from the Shiller monthly series, each year scaled to the official annual return from S&P Dow Jones Indices. Educational tool, not investment advice — past performance does not predict future returns.

How to Use the Dollar-Cost Averaging Calculator

A monthly amount and two years is all it takes.

1

Enter your monthly amount

Type how much you'd invest each month — for example $500, the way an automatic transfer works.

2

Pick the years

Choose the year you started and the year you stopped, anywhere from 1950 to 2025.

3

Read the result

See the final value, total invested and annual return — plus what a lump sum would have done and a year-by-year breakdown.

Frequently Asked Questions

What is dollar-cost averaging?
Dollar-cost averaging (DCA) means investing a fixed amount of money at regular intervals — say $500 every month — regardless of the price, instead of investing one lump sum. When prices are low your fixed amount buys more shares, and when prices are high it buys fewer, so you spread your entry across many prices. It is how most people actually invest through a paycheck or automatic transfer, and it removes the pressure of trying to time the market. This calculator backtests that strategy against the real history of the S&P 500.
How does this DCA calculator work?
Enter a monthly amount and a start and end year. The calculator invests that amount at the start of each month and grows every contribution forward using the S&P 500's real total return (dividends reinvested) through the end of the last year. It reports the final value, the total you put in, the overall return, and the money-weighted annual return (the internal rate of return, which accounts for the fact that later contributions had less time to grow). It also shows what the same total would be worth if you had invested it all at once at the start, so you can compare dollar-cost averaging with lump-sum investing.
Where does the data come from?
The built-in monthly S&P 500 total-return index runs from 1950 to 2025 and reinvests dividends. Its month-to-month shape comes from the Shiller monthly S&P 500 series, and each calendar year is scaled so its annual return exactly matches the official figure from S&P Dow Jones Indices — so this tool stays consistent with the S&P 500 Return (lump-sum) calculator. Everything runs in your browser from that built-in table; nothing you type is sent anywhere.
Is dollar-cost averaging better than investing a lump sum?
Historically, investing a lump sum all at once has usually beaten dollar-cost averaging the same money, because markets rise more often than they fall, so money invested earlier has more time to grow. DCA tends to win only when the market falls after you start, as in a flat or declining stretch. But that is not the whole story: most people do not have a lump sum to invest and are instead saving from income, for whom DCA is simply how investing happens — and it reduces the risk and regret of putting everything in right before a downturn. Use the lump-sum comparison here to see the difference for any period, and remember this is an educational backtest, not investment advice.

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