Input panel
Try an example
Result appears here
Enter values above, then calculate. Use the output to inspect the assumptions—not to predict a return.
Tool / portfolio maths
DCA and average price calculator
A dollar-cost averaging or DCA calculation can show how multiple purchases change your average entry price. It does not prove that adding more capital is wise. The tool is a maths exercise to make total exposure and blended cost visible before you make a decision.
Runs in your browserNo account · No API key
local only
How to use it
Numbers are clearer when the assumptions are visible.
Start with the default example. Change one input at a time and notice which part of the result moves. Then read the explanation below before using any real-world number.
- Use your account currency consistently.
- Include costs and uncertainty outside the simple model.
- Verify the product’s own contract or fee rules.
How a blended average is calculated
The old position’s cost is existing units multiplied by existing average price. The new purchase cost is new units multiplied by new price. Add the costs and divide by total units. The result is a weighted average, so a larger purchase has a larger influence.
The calculation ignores selling, fees, taxes and changes in the asset itself. Treat it as a recordkeeping aid, not a reason to add to a losing position.
Working modelAverage price = (old cost + new cost) ÷ (old units + new units)
DCA changes exposure as well as average price
A lower average price can look emotionally reassuring, but the account now has more money exposed to the asset. If the asset continues lower, the absolute loss can be larger even while the average price improves.
Before adding, write the reason, maximum allocation, time horizon and what would invalidate the thesis. A scheduled contribution plan is different from repeatedly adding because the market moved against you.
Common questions
Before you move on
Is DCA guaranteed to beat a lump sum?+
No. Results depend on the path of prices, contribution timing, fees and the asset’s eventual performance.
Does the calculator include fees?+
No. Add fees separately to your records or use the real transaction statements.
Can I use it for stocks?+
Yes, as a simple weighted-average exercise, provided you account for fractional shares, fees and the broker’s reporting method.