Stock Position Calculator: Average Cost, Partial Sell & Re-Entry
A practical tool for investors to quickly calculate realized gains from partial sells, the new average cost after adding positions, and the required buy-in to reach a target cost basis. Whether you are trading U.S., Hong Kong, or Taiwan stocks, this calculator helps you understand your cost structure and potential returns, supporting more informed investment decisions.
Partial Close Realized P/L
Realized P/L0.00USD
Realized Return (%)0.00%
Shares Remaining0
Remaining Avg. Cost0.00USD
Portfolio Break-even Price--USD
Average Cost & Target Backsolve
Estimated Cash Required
0.00USD
Add-on vs. Original Position
0.00%
Total Shares After Add-on0
New Average Cost0.00USD
FAQs
What is the average cost (cost basis) of a stock position?
The average cost, or cost basis, is the weighted average price you paid for your shares.
It reflects your true entry level after factoring in multiple buys at different prices.
Why should I calculate partial sell gains?
Selling part of your position allows you to lock in some profits or reduce risk.
Calculating partial sell gains helps distinguish realized profit from the remaining unrealized position.
What is the benefit of the target average price back-calculation?
If you aim to lower your average cost to a desired level, this feature shows how many shares you need to buy and how much capital is required. It helps plan averaging-down strategies more effectively.
Which markets does this tool apply to?
The calculator works for any stock market — U.S., Hong Kong, Taiwan, or others — as long as you input share quantities and prices.
Privacy & data Policy
All calculations run in your browser.
Your inputs are not uploaded or stored and nothing is written to our server database. Closing or refreshing the page clears your entries (aside from your browser’s own autofill). For educational use only–not investment advice.