Finance / Investing
Dollar-Cost Averaging Calculator (Average Cost)
See what investing a fixed amount at regular intervals bought you: the units, the average cost per unit, the value at today's price, and how it compares with investing everything at the first price, from prices you enter.
Dollar-Cost Averaging Calculator (Average Cost): Each purchase buys amount ÷ price units, so low prices buy more. Total invested ÷ total units is your average cost, which is always at or below the simple average of the prices. Investing 100 at 50, 42, 38, 45, 55, and 60 buys 12.72 units at an average 47.17, against a simple average price of 48.33, worth 763 at 60. Runs 100% locally in your browser with zero server file uploads.
- Category
- Business & admin tools
- Runs
- In your browser
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- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
| Purchase | Price | Units bought |
|---|---|---|
| 1 | 50 | 2 |
| 2 | 42 | 2.381 |
| 3 | 38 | 2.6316 |
| 4 | 45 | 2.2222 |
| 5 | 55 | 1.8182 |
| 6 | 60 | 1.6667 |
Investing the same amount each time buys more units when the price is low and fewer when it is high, so the average cost per unit is below the simple average of the prices. Enter the prices you actually paid; nothing is looked up. Whether investing gradually beats investing all at once depends on how prices moved, which the last line compares. This is arithmetic on your figures, not investment advice.
A worked example
Investing 100 a month at prices of 50, 42, 38, 45, 55, and 60 buys 2, 2.38, 2.63, 2.22, 1.82, and 1.67 units: 12.72 in all for 600, an average of 47.17. At 60 they are worth 763, a 27% gain; 600 invested at the first price of 50 would be worth 720.
For the profit on a single buy and sell, use the crypto profit calculator.
Using real prices
Use the price you actually paid each time, including any spread. For a fund bought monthly, your broker's statement lists each purchase's price and units.
To see how regular saving grows at a steady rate instead, use the compound interest calculator.
How to use it
- Enter the amount invested each time.
- List the price at each purchase in order, and optionally today's price.
- Read the average cost, units, value, and gain, and the table of purchases.
Privacy & limitations
Your figures stay in your browser; no prices are looked up.
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Frequently asked questions
Is dollar-cost averaging better than investing at once?
Not on average: markets have usually risen, so a lump sum invested earlier has tended to do better. Averaging reduces the regret and risk of investing everything just before a fall.
Why is my average cost below the average price?
Because the same amount buys more units at lower prices, the low prices weigh more in the average. The average cost is the harmonic mean of the prices.
Can I use it for crypto or a single stock?
Yes: it is arithmetic on the prices you enter. Fees per purchase are not included.
Free tool · runs in your browser · no account required