Dollar-Cost Average Calculator — Free
Calculate accumulated units and average cost when the same cash amount is invested at each listed price. This explains equal-cash purchases without forecasting prices or proving a strategy superior.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
Numbers stay on your device. Nothing is sent to a server.
How to use this tool
Enter cash per purchase and one positive price per line. Blank or invalid entries can be skipped, so check that the reported purchase count matches the intended record.
Results and examples
USD 100 invested at prices of 10 and 20 buys ten and five units, respectively. USD 200 divided by fifteen units averages about USD 13.33, not the simple price average of USD 15.
Limitations
- Fractional units are assumed and fees or spreads are excluded.
- Dividends, tax and outperformance over lump-sum investing are not established.
Fields
| Field | Guidance and constraints |
|---|---|
| Cash each buy | Accepted range: 0.01–1000000 · Input step: 1 |
| Prices paid (one per line) | Check the unit and format displayed beside this field. |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Sources
Frequently asked questions
Why do lower prices buy more units?
USD 100 invested at prices of 10 and 20 buys ten and five units, respectively. USD 200 divided by fifteen units averages about USD 13.33, not the simple price average of USD 15.
Does this prove an advantage over lump-sum investing?
Fractional units are assumed and fees or spreads are excluded. Dividends, tax and outperformance over lump-sum investing are not established.
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