Dollar-Cost Averaging Calculator
Calculate returns from a dollar-cost averaging strategy. See how regular investing performs over time.
Investing $300 a month at an 8% annual return grows to about $176,706 over 20 years, turning $72,000 of contributions into $104,706 of investment gain.
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What Is Dollar-Cost Averaging?
DCA is investing a fixed amount at regular intervals, regardless of market conditions. You buy more shares when prices are low and fewer when high, averaging your cost over time.
Worked example
Using the defaults — $300 a month invested for 20 years at an 8% annual return:
With monthly compounding, r = 8% ÷ 12 = 0.0066667 and n = 240 months.
Total what you put in. $300 × 240 = $72,000. That is the amount actually transferred, and it is the only figure that is certain.
Compute the annuity factor. ((1.0066667)^240 − 1) ÷ 0.0066667 = 589.02. Multiplying by $300 gives $176,706, the projected end value.
Isolate the gain. $176,706 − $72,000 = $104,706 of investment return. Growth exceeds contributions in dollar terms for the first time at roughly year 14 — before that, most of the balance is money you saved.
See what DCA actually changes. DCA does not improve the expected return; it changes the shape of the risk. Instead of one entry price, you buy at 240 of them. In a market that trends upward — historically the usual case — that normally produces a slightly lower return than investing the whole sum on day one, because the cash sits uninvested for longer.
Enter 300, 8 and 20 above to reproduce the $176,706 figure. The model assumes the contribution is made at the start of each month and that the return is constant, which no real sequence delivers.
The same $300 a month across returns and horizons
Contribution amount is fixed; the return and the horizon both change the outcome, and the horizon matters more.
| Horizon | At 5% | At 8% | At 10% | Contributed |
|---|---|---|---|---|
| 10 years | $46,585 | $54,884 | $61,453 | $36,000 |
| 20 years (default) | $123,310 | $176,706 | $227,811 | $72,000 |
| 30 years | $249,748 | $447,108 | $678,146 | $108,000 |
| 40 years | $457,783 | $1,047,302 | $1,897,377 | $144,000 |
Monthly compounding, contributions at the start of each month. Doubling the horizon from 20 to 40 years multiplies the 8% outcome by 5.9 while only doubling the money contributed — the clearest illustration of why the horizon dominates the return assumption.
Common mistakes with this calculation
- Believing DCA beats lump-sum investing. Across most historical periods and markets, investing a lump sum immediately outperforms spreading it out, because markets trend upward and cash drags. DCA wins about a third of the time. Its real value is behavioural — it makes people actually invest — not statistical.
- Confusing DCA with a monthly contribution plan. Strictly, DCA means taking money you already have and spreading it into the market over a period. Investing part of each paycheck is just regular saving. The two are often conflated, and the distinction matters when comparing against a lump-sum alternative.
- Assuming a diversification benefit where there is none. DCA reduces the risk of entering all at once. It does not reduce the risk of the market itself. A portfolio built through DCA still loses value in a bear market, and a long accumulation period still ends with a concentrated balance.
- Ignoring costs and the drag of uninvested cash. Transaction fees, commissions and the spread on each purchase matter more when you make 240 small purchases than when you make one large one. Meanwhile the uninvested portion of a DCA schedule earns little or nothing, which is exactly what the return comparison measures.
When this calculator does not apply
- It assumes a constant return of 8%. Real returns arrive as a volatile sequence, and the order of those returns drives the outcome.
- It assumes every contribution is made on time with no gaps, which real life rarely delivers.
- It does not model dividends, capital gains distributions, or the tax drag of holding funds in a taxable account.
- It excludes fund expense ratios, trading commissions, and any advisory fee.
- It cannot capture the behavioural benefit of DCA, which for many investors is its main practical advantage.
Frequently Asked Questions
Is DCA better than lump-sum investing?
Statistically, lump-sum investing outperforms DCA about 66% of the time because markets trend upward. However, DCA reduces timing risk and is psychologically easier for many investors.
What are the risks of DCA?
In a strongly rising market, DCA means some of your money is uninvested and misses gains. There is also market risk - your investments can lose value.
Sources & Methodology
This calculator uses standard financial formulas. See our methodology page for the full formula derivation.
- Dollar-Cost Averaging US Securities and Exchange Commission
- Mutual Fund and ETF Fees and Expenses US Securities and Exchange Commission
- Compound Interest Calculator US Securities and Exchange Commission
- Financial Accounts of the United States Federal Reserve
- Investor Bulletins US Securities and Exchange Commission
Last reviewed .
Key takeaways
- $300 a month at 8% for 20 years reaches about $176,706 on $72,000 of contributions.
- The $104,706 gain comes entirely from compounding; the contribution amount is unchanged.
- Horizon beats rate: doubling the period multiplies the outcome far more than raising the assumed return.
- DCA does not beat lump-sum investing most of the time. Its value is behavioural, not statistical.
- Growth overtakes contributions in dollar terms at roughly year 14 on this schedule.