Dollar Cost Averaging Calculator
Enter how much you invest each period and the price at every purchase to see units owned, your average cost, current value and profit, compared with investing the lump sum on day one. Everything is calculated privately in your browser.
Investment plan
Price per period
Purchase schedule
For education only, not investment advice. Results ignore taxes, dividends and the time value of money. Past prices do not predict future returns.
How to use the Dollar Cost Averaging Calculator
- Enter the amount you invest per purchase and how often you buy (week, 2 weeks, month, quarter or year).
- Type the price for each period in the price list, add periods with + Add period, or press Paste a column to drop in prices from a spreadsheet.
- Add fees if your broker or exchange charges a fixed fee or a percentage per trade.
- Set the current price, or leave it blank to value your holdings at the last price in the list.
- Read the results: units owned, average cost, current value, profit and the lump-sum comparison, then switch charts or download the schedule as CSV.
Dollar cost averaging formulas
For every purchase i with amount A, price Pi and fee Fi:
- Units bought = (A − Fi) ÷ Pi
- Total invested = A × number of purchases (fees included)
- Average cost per unit = total invested ÷ total units owned
- Current value = total units × current price
- Profit or loss = current value − total invested, and in percent ÷ total invested
- Lump sum = (total invested − one fee) ÷ first price × current price
Because a fixed amount buys more units when the price is low, the no-fee average cost equals the harmonic mean of your purchase prices. The harmonic mean is always less than or equal to the simple (arithmetic) average, which is the mathematical reason DCA buyers pay less per unit than the average price over the same period.
Worked example
You invest $100 a month for four months at prices of $10, $8, $5 and $10.
| Month | Price | Invested | Units bought | Total units |
|---|---|---|---|---|
| 1 | $10 | $100 | 10 | 10 |
| 2 | $8 | $100 | 12.5 | 22.5 |
| 3 | $5 | $100 | 20 | 42.5 |
| 4 | $10 | $100 | 10 | 52.5 |
Total invested is $400 for 52.5 units, so the average cost is $400 ÷ 52.5 = $7.62, while the average price was ($10 + $8 + $5 + $10) ÷ 4 = $8.25. At the final price of $10 the position is worth $525, a profit of $125 (31.25%). Investing $400 at the first price of $10 would have bought 40 units worth $400, so in this falling-then-recovering market DCA came out ahead. In a market that only rises, the lump sum wins.
Tips for using DCA
- Watch the fees. A $1 fee on a $50 purchase is a 2% cost on every buy. Choose a broker with free recurring buys or invest less often in larger amounts.
- Automate it. The benefit of DCA comes from sticking to the schedule, especially when prices fall.
- Compare with growth projections. For a smooth expected return instead of real prices, use the compound interest calculator, and check your annualized return with the CAGR calculator.
Frequently asked questions
What is dollar cost averaging?
Dollar cost averaging (DCA) means investing the same amount of money at regular intervals regardless of the price. When the price is low your fixed amount buys more units and when it is high it buys fewer, so your average cost per unit ends up at the harmonic mean of the prices you paid, which is never higher than their simple average.
How is the average cost per unit calculated?
Average cost = total money invested ÷ total units owned. Fees are included in the money invested, so they raise your average cost. With equal purchase amounts and no fees this equals the harmonic mean of the purchase prices.
Is dollar cost averaging better than investing a lump sum?
Not always. Studies of stock markets (for example Vanguard's research) found that investing a lump sum immediately beat DCA roughly two thirds of the time because markets tend to rise over time. DCA reduces the risk of investing everything right before a drop and helps build a habit. This calculator shows both results for your own price list.
Can I use this for crypto, ETFs or individual stocks?
Yes. Enter the price of any asset at each purchase: a share price, an ETF price, a fund unit price or the price of one bitcoin. Fractional units are supported, so small purchases of expensive assets work too.
How do I paste prices from a spreadsheet?
Press Paste a column and paste one price per line. You can copy a single column from Excel or Google Sheets, or rows like 2025-01-31, 105.20; the calculator takes the last number on each line and ignores headers.
Does the calculator include dividends or taxes?
No. It calculates the value of the units you bought from your price list. Reinvested dividends, capital gains taxes and inflation are not included, so treat the result as a pre-tax, price-only return.