Stock Water Buy
Solve for the additional whole-share quantity needed to lower an existing average cost to a target. This is arithmetic under an assumed purchase price, not a recommendation to buy more or a promise of recovery.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
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How to use this tool
Enter current quantity, average cost, new buy price and target average. The buy price must be below the target and the target below the old average; required quantity rounds up to whole shares.
Results and examples
With ten shares averaging 100, buying another ten at 50 produces an average of 75. The lower average comes with more invested capital and more units exposed to further price declines.
Limitations
- Fees, taxes, execution-price movement and fractional-share rules are excluded.
- A target equal to the new buy price cannot exactly erase a higher old cost using a finite purchase.
Fields
| Field | Guidance and constraints |
|---|---|
| Shares held | Check the unit and format displayed beside this field. |
| Average cost (KRW) | Check the unit and format displayed beside this field. |
| Current price (KRW) | Check the unit and format displayed beside this field. |
| Target average cost (KRW) | 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
How can an average of 100 become 75?
With ten shares averaging 100, buying another ten at 50 produces an average of 75. The lower average comes with more invested capital and more units exposed to further price declines.
Does a lower average remove loss risk?
Fees, taxes, execution-price movement and fractional-share rules are excluded. A target equal to the new buy price cannot exactly erase a higher old cost using a finite purchase.
