株式平均取得単価計算機
異なる価格で株式を購入したときの1株あたりの平均コストを計算します。
入力
平均単価
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Calculating Your Average Stock Purchase Price
概要
When you buy the same stock at several different prices, your average cost per share — not any single purchase price — determines your profit or loss. This calculator adds up multiple buys and returns the total shares, total cost, and weighted average price, so you always know your true break-even. It runs in your browser and stores nothing.
使い方（ステップ）
- 1
Enter each purchase
Add the number of shares and price for every buy you made.
- 2
Add more rows as needed
Include every transaction so the average reflects your full position.
- 3
Read your average price
This weighted average is your break-even price per share.
仕組み
The average price is a weighted average: total amount invested ÷ total shares bought, not a simple average of the prices. Buying more shares at a lower price pulls your average down (often called averaging down); buying at higher prices pulls it up. Knowing this number tells you exactly what price the stock must reach for you to break even.
こんなときに使う
Tracking your cost basis after several purchases of the same stock. Deciding whether averaging down meaningfully lowers your break-even. Planning a target sell price relative to your true average cost.
よくある質問
Because you usually buy different quantities at each price. A weighted average accounts for how many shares you bought at each level, which is your real cost basis.
注意事項
This tool performs arithmetic on the figures you enter and is not investment advice. Past prices do not predict future results — consult a licensed financial advisor before making investment decisions.