Combine multiple buy orders (lots) of the same stock to find your average cost per share, also known as 'averaging down'.
When you buy shares of the same stock at different prices over time, your true cost basis is the weighted average of every purchase - not any single price. This calculator blends all your buy orders ("lots") into one average price per share.
Average Price = Total Cost of All Lots ÷ Total Shares Owned
You buy 10 shares at $50 and later 15 shares at $38. Total cost = $500 + $570 = $1,070 for 25 shares, giving an average price of $42.80 per share.
Why does average cost matter? It tells you the real break-even price you need the stock to reach before you're in profit.
Total amount spent across purchases divided by total shares purchased.
Buying additional shares after a price drop, lowering your overall average cost per share.
It's the baseline for determining whether your position is profitable.