What is dollar-cost averaging (DCA)?

Dollar-cost averaging (DCA) is an investment strategy where you invest a fixed amount at regular intervals — weekly, monthly or quarterly — regardless of the market price. By doing so, you buy more shares when prices are low and fewer when prices are high, reducing the impact of market volatility on your average purchase price.

Is DCA better than lump sum investing?

Mathematically, lump sum investing tends to outperform DCA in consistently rising markets because more capital is invested and compounding for longer. However, DCA reduces timing risk and emotional stress, making it the more practical choice for most investors who cannot predict market movements. Our vs Lump Sum tab calculates the exact difference for any scenario.

How do I calculate my average cost basis with multiple purchases?

Average cost basis = Total Amount Spent / Total Shares Purchased. For example, if you bought 10 shares at $50 and 20 shares at $40, your average cost is ($500 + $800) / 30 = $43.33. Our Cost Basis tab calculates this automatically for unlimited purchases, then shows your unrealized P&L when you enter the current price.

How much do I need to invest monthly to reach $1 million?

It depends on your time horizon and expected return. At 10% annual return over 30 years, you need approximately $442/month. Over 20 years, approximately $1,317/month. Use the Goal Planner tab to calculate the exact monthly contribution required for any target amount, starting investment, time period and expected return.

Does this DCA calculator account for inflation?

Yes. In the DCA Planner tab, you can optionally enter an inflation rate. The calculator then displays both the nominal final portfolio value and the inflation-adjusted (real) value, showing the true purchasing power of your future portfolio.

What contribution frequency should I choose for DCA?

Monthly is the most common DCA frequency, aligning with salary cycles. Weekly DCA provides slightly better cost averaging due to more purchase points, but the difference is small over long periods. Our DCA Planner supports weekly, monthly, quarterly and annual frequencies so you can compare the impact of each.

Is this DCA calculator free?

Yes. The DCA Calculator Pro on StockToolHub is completely free to use with no registration or account required.

DCA Calculator Pro — Dollar-Cost Averaging Tool

Investment Setup

Initial Investment (optional)

One-time lump sum invested at the start

Regular Contribution

Contribution Frequency

Time Period

Years

Months

Return Assumptions

Expected Annual Return

S&P 500 historical avg ≈ 10%/yr

Inflation Rate (optional)

Shows inflation-adjusted real value

Final Portfolio Value

—

Enter values to calculate

Total Invested

—

Total Gain

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ROI on Capital

—

Return Multiple

—

Portfolio Growth Over Time

Purchase History

Buy Price ($)	Shares / Units	Total Cost

Current Market Price (optional)

Enter to calculate unrealized P&L

Average Cost Basis

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per share / unit

Total Shares

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Total Invested

—

Current Value

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Unrealized P&L

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P&L Percentage

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Purchase Prices vs Average Cost Basis

What each tab calculates

DCA Planner

Project your final portfolio value from regular contributions at any frequency — weekly, monthly, quarterly or annual — with optional inflation adjustment and initial lump sum.

vs Lump Sum

Compare investing all your capital on Day 1 (lump sum) against spreading it in equal monthly instalments (DCA). Same capital, different timing — see which wins.

Cost Basis

Calculate your average cost per share across multiple purchases at different prices. Enter the current price to instantly see your unrealized profit or loss.

Goal Planner

Set a financial target and work backwards — the calculator tells you exactly how much to invest each month to reach your goal within your chosen timeframe.