DCA Compound Calculator

This calculator uses the future-value-of-an-annuity formula for end-of-period contributions, converting the annual return into a monthly rate compounded each period. Results are for illustration only and are not investment advice — actual returns vary with market movements, fees, and taxes. See our disclosure.

How to use the DCA compound calculator

1. Under Contribution per period, enter the fixed amount you invest each month — for example, 10,000 per month.
2. Under Number of periods, enter how many months in total you plan to invest — 120 means investing steadily for 10 years.
3. Under Expected annual return, enter the yearly return you assume; the tool converts it into a monthly rate for compounding automatically.
4. All four results update instantly: total contributions, ending value, cumulative gain, and return rate.
5. Click Copy results to copy all four figures at once, or Reset to return to the default values.

This tool models the most common dollar-cost-averaging scenario: a fixed amount contributed at the end of each month, assuming the same monthly return every period. When you set the annual return to 0, the ending value simply equals your total contributions, which is handy for seeing how much principal you would accumulate on its own.

How DCA compounding is calculated

The core idea of dollar-cost averaging (DCA) is to invest a fixed amount every period regardless of whether the market is high or low. With a contribution per period of PMT, a monthly return of i, and n periods, the ending value uses the future-value-of-an-annuity formula:

Ending value = PMT × [ (1 + i)ⁿ − 1 ] ÷ i

The monthly return i is the annual return divided by 12. For example, a 7% annual return works out to roughly 0.583% per month. Total contributions are simply "amount per period × number of periods," and cumulative gain is "ending value − total contributions." One key idea worth noting: the earlier a contribution goes in, the longer it compounds, so in later years your gains grow noticeably faster than your principal accumulates. That is the power of compounding.

Keep in mind that this formula assumes a fixed return every period, but real markets never hand you the same return month after month — they rise and fall. So the numbers here are a theoretical estimate "under a fixed-return assumption": great for understanding the compounding trend, but not a guarantee. To also see the compounding effect of a single lump-sum investment, pair this with the compound interest calculator.

Frequently asked questions

What is the difference between DCA and lump-sum compound calculations?

A lump-sum investment puts one amount in at the start and adds nothing afterward, so compounding applies only to that single principal. DCA, by contrast, adds a new contribution every period, and each contribution starts compounding at a different time — the earlier ones compound for longer. So for the same total amount, splitting it into a DCA schedule weights the earlier contributions more heavily, and the long-run compounding effect usually differs from a one-time investment. This tool calculates the DCA scenario; if you want a one-time investment, use the compound interest calculator instead.

What annual return should I enter?

There is no standard answer — it depends on what you invest in. Enter a figure you estimate yourself or draw from a historical average; the tool will not judge whether it is reasonable. Bear in mind that past returns do not predict the future, and a higher assumed return usually comes with higher volatility and risk. It helps to try several numbers (say a conservative, neutral, and optimistic figure) to see the range of outcomes rather than relying on a single value.

Does the result include fees and taxes?

No. This tool only performs a straightforward future-value-of-an-annuity compound calculation; it does not account for trading fees, management fees, taxes, or inflation. Your actual take-home return will be somewhat lower than the theoretical value. If you want a figure closer to reality, lower the annual return a little (for example, subtract your estimated annual fee rate) before calculating.

Is my input data saved?

No. Every calculation runs locally in your browser. The amounts and returns you enter are never sent to any server, and they are not logged or stored. You can test as many scenarios as you like with peace of mind.