Dollar Cost Averaging Calculator
Shares bought and the average cost per share from regular purchases at the prices you enter, against the average price, and a lump sum compared with spreading the same money out.
Result…
How it's calculated
Shares each time = (amount − fee) ÷ price Average cost per share = total invested ÷ total shares Average price = sum of prices ÷ number of purchases Steady return: lump sum = total × (1 + r)^n; DCA = (total ÷ n) × Σ (1 + r)^(n − i), i = 0 … n − 1
Dollar cost averaging (DCA) means investing a fixed amount at regular intervals instead of all at once. Because a fixed amount buys more shares when the price is low and fewer when it is high, the average cost per share ends up at or below the simple average of the prices you paid. Enter the price at each purchase and either the same amount each time or the amounts you actually invested, and the page shows shares bought, average cost, the value at today's price and what a single purchase at the first price would be worth now. The second mode compares a lump sum with spreading the same total over several months at a steady monthly return, which shows why a lump sum wins in a steadily rising market and DCA in a falling one.
Your numbers, step by step
About the Dollar Cost Averaging calculator
This dollar cost averaging calculator works for any currency. Dollar cost averaging (DCA) means putting a set amount into an investment at regular intervals instead of all at once. Enter the price at each purchase and either the same amount every time or the amounts you actually invested, and the calculator gives the shares you bought, your average cost per share, the simple average of the prices, and what the holding is worth now. It also shows what the same total would be worth if you had invested it all at the first price. A second mode compares a lump sum with spreading it over several months at a steady monthly return you choose, so you can see when each approach comes out ahead. Every step uses your numbers, and fees per purchase can be included. For long-term growth with regular deposits, see the investment calculator.
How to use it
- Choose “A list of purchase prices” to analyse real purchases, or “A steady monthly return” to compare a lump sum with DCA.
- For purchases, pick “Same amount” or “Amounts I enter”, then fill in the “Price per share at each purchase”, oldest first.
- Add any “Fee per purchase”, and a “Price now (optional)” to value the shares today.
- For the comparison, enter the “Total to invest”, how many months to “Spread over” and the “Monthly return”.
Worked example
You invest 500 at each of six prices: 50, 45, 40, 48, 55 and 52. That buys 62.73 shares for 3,000, an average cost of 3,000 ÷ 62.73 = 47.82 a share, below the average price of 48.33. At the last price of 52 the shares are worth 3,262.17, while 3,000 invested at the first price of 50 would be worth 3,120, so DCA is ahead by 142.17. In the second mode, spreading 12,000 over 12 months when prices fall 1% a month ends at 11,247.90, against 10,636.62 for the lump sum.
Updated
Questions people ask
How do I calculate my average cost per share?
Divide the total you invested by the total number of shares you hold. Each purchase buys amount ÷ price shares, so add those up first, then divide the money by the shares.
Why is my average cost lower than the average price?
With the same amount each time, you buy more shares when the price is low and fewer when it is high, so the cheap purchases carry more weight. The average cost is then at or below the simple average of the prices.
Is a lump sum or dollar cost averaging better?
In a market that rises steadily, the lump sum ends ahead because all the money is invested for longer. In a falling market DCA ends ahead. Real prices move up and down, so the result depends on the order of good and bad months.
What is a common mistake when working out DCA results?
Taking the simple average of the prices as your cost. That is only right if you bought the same number of shares each time; with equal amounts, use total invested ÷ total shares.
What does a DCA comparison leave out?
Dividends, taxes, currency changes and any interest on money waiting to be invested. It describes the numbers you enter and is not financial advice; a licensed adviser can help you decide how to invest.