Stock Average Calculator
Work out your average buy price across two purchases of the same stock.
Your inputs
Add more purchases by re-running the calculator with your new average price as the first lot.
Estimates only. Figures are indicative and do not constitute financial advice.
About the Stock Average Calculator
Bought the same stock at two different prices and want to know your real average cost? "Stock average calculator" (also called an average down calculator) is exactly what long-term investors and traders search for when averaging into a position — especially after buying more shares at a lower price to bring down their overall cost basis.
The math is simple in principle but easy to get wrong doing it in your head: your average price isn't just the average of the two prices, it's weighted by how many shares you bought at each price. This calculator takes two purchase lots (quantity and price for each) and computes your total shares, total investment, and true weighted average price per share. This is useful for tracking your actual cost basis for tax purposes, deciding whether 'averaging down' after a price drop actually makes sense for your position, or simply keeping an accurate personal record. For more than two purchase lots, run the calculator again using your first result's average price and combined quantity as the new 'first purchase.'
How to use this calculator
- Enter the quantity and price of your first purchase.
- Enter the quantity and price of your second purchase.
- See your total shares, investment, and average price.
Frequently asked questions
›What is averaging down in stock investing?
It means buying more shares of a stock you already own at a lower price than your original purchase, which reduces your overall average cost per share.
›Does averaging down always help?
Not necessarily — it lowers your average cost, but only helps if the stock recovers; if it keeps falling, you've now invested more in a declining position.
›How do I calculate average price for more than two purchases?
Combine your first two using this calculator, then use that result's average price and total quantity as the 'first purchase' for a third calculation, and repeat for additional lots.
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Read the full guide
How to Calculate Your Average Stock Buy Price