Tools · Calculator
Dollar-cost averaging calculator
See how many shares a fixed amount buys when it is invested at regular intervals, and what the average cost comes to, at a steady price or a changing one.
An illustration, not a recommendation. This calculator shows what a fixed amount buys at each period's price. It doesn't say whether anyone should invest on a schedule, and it doesn't forecast prices.
The formula
Shares bought in a period = amount invested ÷ price that period
Average cost = total invested ÷ total shares
If you enter a price change, each period's price is the previous price times (1 + the change). The last column of the table is a running total of shares.
A worked example
Investing 200 at the end of each of 12 periods, at a steady price of 50, buys 200 ÷ 50 = 4 shares each time. After 12 periods that is 48 shares. The total invested is 2,400, and the average cost is 2,400 ÷ 48 = 50, the same as the price.
The picture changes when the price moves. The same 200 a period, with a first price of 50 that falls 5% each period, buys 4 shares in period 1 and 200 ÷ 47.50 ≈ 4.21 shares in period 2. After 12 periods that is about 64.65 shares. The average cost is about 37.12, the last price is about 28.44, and those shares would be worth about 1,838.56. The same 2,400 spent all at once at the first price would have bought 48 shares, worth about 1,365.12 at that last price. If the price had risen instead, the share-count comparison would run the other way. The calculator reports both results; it doesn't pick one.
Related calculators
The compound growth calculator grows a starting amount at a rate you choose, with an optional amount added each year. The savings goal calculator turns that around and asks how long a schedule of additions takes to reach a target.
Common questions
What is dollar-cost averaging?
Investing the same amount of money at regular intervals, so each purchase buys however many shares that amount covers at that period's price. When the price is lower, the same amount buys more shares; when it's higher, it buys fewer.
How is the average cost worked out?
Add up the money invested and divide by the shares accumulated. It is a share-weighted average of the prices, not a simple average of the price list.
What if the price never changes?
Then each period buys the same number of shares, and the average cost equals the price. The table still shows the running total.
Does this say whether a schedule of purchases beats buying all at once?
No. The calculator only shows the arithmetic at the prices you enter. Which path ends with more shares depends on how the price moves, and nothing here is a forecast or a recommendation.
Can I use this for any currency or any length of period?
Yes. A period can be a week, a month or a year, and the units can be any currency, as long as the amount and the price use the same one.
Disclosures
- Editor holdings
- The editor holds no position in any company named on this page. As of Nov 11, 2026.
- Compensation
- Nobody paid for this calculator. No affiliate links on this calculator.
- Sources
- Each company's own SEC filings, linked next to each number.
- Last updated
- Nov 10, 2026
General education, the same for every reader. Not a recommendation to buy, sell or hold any security, and it doesn't consider your situation.
More in Learn and Tools · Methodology & Disclosures explains where every number comes from.