Dollar-Cost Averaging Calculator

Average cost, units and profit from investing a fixed amount over time

Work out your average cost per share, total units bought and current profit when you invest a fixed amount at a series of prices — and compare dollar-cost averaging against a single lump-sum buy. Runs 100% in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

Last updated Source: Gera Tools

What is dollar-cost averaging?

Dollar-cost averaging (DCA) means investing a fixed amount at regular intervals regardless of price. When the price is low your fixed amount buys more units; when it is high it buys fewer. Over time this smooths your average purchase price and removes the need to time the market.

The Dollar-Cost Averaging Calculator shows what happens when you invest a fixed amount at a series of prices: how many units you accumulate, your average cost, and how that compares with putting all the money in at once.

How averaging works

For each purchase:

units bought = amount invested ÷ price

Your blended cost is then:

average cost per unit = total invested ÷ total units

Because a fixed amount buys more units when the price is low and fewer when it is high, the average cost is pulled toward the cheaper prices — which is the core benefit of dollar-cost averaging.

Worked example

Investing 300 at prices of 10, 12, 8 and 15:

PriceAmountUnits bought
1030030.00
1230025.00
830037.50
1530020.00

Total invested is 1,200 for 112.5 units, an average cost of 1,200 ÷ 112.5 ≈ 10.67 — below the simple average price of 11.25, because more units were bought when the price was low. The tool also shows your current value and profit at the latest price you enter, and a lump-sum comparison.