Stock Average Price & Average Down Calculator
Know your real break-even price.
Add each purchase below and see your true average price across all of them — whether you're averaging down on a loser or adding to a winner, this shows exactly what it takes to get back to even. Updates live, and your entries stay saved in this browser — nowhere else.
Keyboard: Tab moves between fields · Enter on the last row adds a purchase · ↑/↓ moves between rows · Ctrl/⌘+Backspace removes the current row.
Fill this in to see your position value, unrealized gain/loss, and the move needed to break even.
Your average price
Enter at least one complete purchase above — both shares and price are required — and your average break-even price appears here instantly.
Step by step
How to use this average price calculator
Enter each purchase as a lot
Shares and price paid for every buy, in any order. This works for averaging down, scaling in, or just auditing a position you've built over months.
Read your true average price
That's your break-even — the price the stock must reach for you to sell and get your money back. Compare it to the current price to see your real unrealized P/L.
Test an average-down before you place it
Add a hypothetical lot at today's lower price and watch your break-even move. If the improvement is smaller than you hoped, that's worth knowing before the money leaves your account.
Drag the price scrubber on the chart
Slide the current price to see how the position's profit or loss changes at any level — including the price that finally gets you back to even.
The number that anchors you
What is your average price and why it matters
Your average price is the weighted mean of everything you paid for a position: total dollars invested divided by total shares owned. It's the price the market has to reach for you to sell and get your money back — which makes it the single most-watched number in most traders' heads, for better and worse.
It matters for practical reasons: it tells you your real exposure, your true break-even point, and whether adding to a position actually improves your setup or just makes you feel better about it. Knowing the number precisely — instead of estimating it — is the difference between managing a position and hoping at it.
But it matters psychologically too. Your average price is information about you, not about the stock. The market doesn't know or care what you paid. Once you understand that, the number becomes a useful piece of arithmetic instead of an emotional anchor — which is exactly what anchoring bias turns it into when you're not watching for it.
Strategy or trap
How averaging down works (and when it's a mistake)
Averaging down is simple math: buy more shares at a lower price, and your average cost drops. Buy 10 shares at $100, then 10 more at $80, and your average is $90 — the stock only needs to recover to $90 instead of $100 for you to break even. Used deliberately, it's a legitimate risk-management technique for positions you still believe in.
The trap is that the same action can be two completely different decisions. Averaging down is sound when it's driven by a fresh, independent thesis: you've re-analyzed the company at $80 and you'd buy it today even if you'd never owned it before. It's a mistake when it's driven by the original entry price — when "lowering my average" is really about defending a past decision and avoiding the admission that it was wrong.
If "lowering my average" is the main reason you're adding to a position, it's worth checking whether that's a fresh decision or sunk cost reasoning — read more about the sunk cost fallacy. And before you add, make sure the new size still fits your risk rules with the position size calculator.
Questions
Average price, answered
How do you calculate average stock price?
Multiply the shares by the price paid for each purchase, add those totals together, then divide by the total number of shares owned. For example: 10 shares at $100 plus 10 shares at $80 is $1,800 invested across 20 shares — an average price of $90. This calculator does that math for as many lots as you add.
What does 'averaging down' mean?
Averaging down means buying more of a stock after its price has fallen below what you originally paid. Because the new shares are cheaper, your average price per share drops. The position still has the same unrealized loss in dollars — what changes is the price the stock needs to reach for you to break even.
Is averaging down a good strategy?
It depends entirely on why you're adding. If you've re-evaluated the business at the lower price and would buy it today even with no prior position, averaging down can be sound. If you're adding mainly to lower your average and defend the original decision, that's sunk cost reasoning — and it's how small mistakes become large ones.
How do I use this as an average down calculator?
Enter your existing position as the first purchase lot, then add the new lot you're considering at the lower price. The calculator instantly shows your new average price and the price the stock must reach for you to break even. Try different share counts in the second lot to see how much each add moves your break-even — before you commit the money.
How many shares do I need to buy to lower my average to a specific price?
There's a formula: shares to buy = (current shares × (current average − target average)) ÷ (new buy price − target average). In practice it's easier to experiment — add a second lot in this calculator and adjust the share count until the average price lands where you want it. Just remember the dollars required grow fast as your target gets closer to the current market price.
How is break-even price different from average price?
For a simple long position with no fees, they're the same number: the price at which you can sell and get your money back. In practice, commissions and fees shift the true break-even slightly higher than the raw average price. This calculator keeps things simple and ignores fees, so treat the result as your approximate break-even.
Before you average down again — check your reasoning.
A lower average price fixes nothing if the thesis is broken. Run your thinking through the Bias Checker before you add.
Check My ReasoningTrack how your averaging decisions actually turn out.
The Decision Journal logs your reasoning, confidence, and outcomes — so you can see whether adding to losers has historically worked for you or against you.
Start your free Decision Journal