About the Dollar Cost Averaging Calculator
Dollar-cost averaging means investing the same amount at regular intervals, whatever the price. When prices are low you buy more shares, and when they are high you buy fewer, so the average cost per share is lower than the average price. Enter the amount and the price at each purchase, and the calculator shows the shares bought, your average cost, the value now and the gain, with a comparison against putting everything in at the start. Type the amount invested each time and the share price at each purchase and the dollar-cost averaging appears at once, with a few related figures underneath, and you can copy the result with one tap. The sums run in your browser, so nothing you enter is uploaded.
Updated October 2026
How to use the Dollar Cost Averaging Calculator
- 1Enter the amount invested each time and the share price at each purchase.
- 2Pick the units or options from the menus if the dollar-cost averaging tool offers them.
- 3Read the dollar-cost averaging in the large result box.
- 4Look at the extra rows for related figures.
- 5Press Copy result to keep the answer.
When you need the dollar-cost averaging
Savers who pay into a fund each month use the idea without thinking about it. The calculator shows how it works with real prices, and helps compare it with investing a lump sum, which wins when prices rise steadily and loses when they fall at first.
Use prices that match your own purchases, such as the closing price on the first day of each month. The optional current price lets you see the value at today's price rather than at the last purchase price.
How the dollar-cost averaging is worked out
Shares bought = amount ÷ price at that purchase. Average cost = total invested ÷ total shares. Gain = (value now − invested) ÷ invested. Investing 100 at prices of 50, 40, 25, 30, 45 and 50 buys 16.06 shares for 600, an average cost of 37.37, lower than the average price of 40. At a final price of 50 the shares are worth 802.78, a gain of 33.8 percent. A lump sum of 600 at the first price of 50 would buy 12 shares worth only 600.
Every answer on this page comes from that one rule, so you can check any result by hand with a calculator. The figures shown underneath, such as other units, are conversions of the same answer.
- Any number of purchases
- Lump-sum comparison
- Optional current price
Mistakes to avoid with dollar-cost averaging
Dollar-cost averaging does not remove risk or guarantee a profit. If prices fall for the whole period, you still lose. It is also not magic: over long periods of rising markets a lump sum often does better, because it is invested for longer. Fees and taxes are not included.
On phone and computer
On a phone, type into the boxes one after another and read the dollar-cost averaging underneath; Copy result puts it on the clipboard for a message or a note. On a computer the inputs sit on the left and the answer on the right, so you can change one figure and watch the dollar-cost averaging move. The dollar cost averaging calculator works the same on both. After running a plan, Stock Average Calculator gives the average price for uneven buys. SIP Calculator is the matching idea for monthly funds, Investment Calculator projects growth, and CAGR Calculator turns the result into a yearly rate.
Features
- Use your real purchase prices
- No guarantee of profit
- Fees raise the cost
- Clear messages when the dollar-cost averaging inputs make no sense
- Copy the result with one tap
- Private: nothing is uploaded
Frequently asked questions
How do I calculate dollar-cost averaging?
Shares bought = amount ÷ price at that purchase. Average cost = total invested ÷ total shares. Gain = (value now − invested) ÷ invested. Investing 100 at prices of 50, 40, 25, 30, 45 and 50 buys 16.06 shares for 600, an average cost of 37.37, lower than the average price of 40. At a final price of 50 the shares are worth 802.78, a gain of 33.8 percent. A lump sum of 600 at the first price of 50 would buy 12 shares worth only 600.
What is the formula for dollar-cost averaging?
Shares bought = amount ÷ price at that purchase. Average cost = total invested ÷ total shares. Gain = (value now − invested) ÷ invested. The dollar cost averaging calculator applies it exactly and rounds only the displayed answer to six significant figures.
Is dollar-cost averaging better than a lump sum?
It reduces the risk of investing everything at a high point, but in rising markets a lump sum usually wins, because the money is in the market longer.
Why is the average cost lower than the average price?
Because you buy more shares when the price is low. The average cost is a harmonic mean of the prices.
Does it include fees?
No. Add trading costs yourself, as they raise your average cost.
Is this dollar cost averaging calculator free and private?
Yes. It is free, needs no account and runs in your browser, so the numbers you type are not uploaded or stored.