Break-Even and Averaging-Down Calculator
Your new average entry and break-even price after adding to a position, alongside what the original position alone would have needed — so the trade-off is visible.
- Total quantity
- 2
- Total cost
- 180.00 USD
- Average entry
- 90
- Break-even price incl. fees
- 90.09
- Move needed from the second price
- 12.61%
- Move needed if you had not added
- 25.13%
- Exposure at current price
- 160.00 USD
The two "move needed" rows are the comparison worth making. Adding to a losing position lowers the break-even price — that part is real arithmetic. It also increases the size of the position that is currently wrong, so the same adverse move now costs more. Both effects are present; only the first is usually noticed.
The arithmetic
average entry = (q₁·p₁ + q₂·p₂) ÷ (q₁ + q₂)
break-even = average entry adjusted for round-trip feesA weighted average, which means the size of the addition matters as much as its price. Doubling the position at a price 20% below the first entry moves the average down by 10%; adding a tenth of the position at the same price moves it by under 2%.
Both effects are real
Averaging down is usually argued about as though one side were obviously right. The arithmetic is less dramatic than either camp:
- It genuinely lowers the break-even. The position needs a smaller recovery than it did. This is not an illusion.
- It genuinely increases exposure. You now hold more of something that has so far moved against you, so the next adverse move costs more than the last one did.
The two rows showing "move needed from here" and "move needed if you had not added" exist to put both on screen at once. The first is why people do it; the second is what it was compared against.
The question the numbers cannot answer
Whether to add comes down to something the calculator has no access to: is the idea more likely to be right now than it was at the first entry?
If the price fell for a reason unrelated to your thesis, adding may be reasonable. If it fell because the thesis is wrong, adding increases a position that is wrong. The arithmetic is identical in both cases, which is precisely why the decision cannot be delegated to it.
The failure mode worth naming: adding because the position is down is a rule about the position, not about the idea. It reliably produces the largest position in the trades that turn out worst, because those are the ones that kept falling.
Where the limits should live
Whatever you decide, the resulting position should still be inside the caps you set before the trade — which is the case for a per-account position cap enforced in code rather than recalculated in the moment. Averaging down is the single most common way a position ends up larger than anything you would have approved at the outset, and it happens one reasonable-feeling step at a time.
Check the result against your original sizing, and if the combined position has drifted past it, that is the answer.
FAQ
How do I calculate my average entry price?
Total cost divided by total quantity — the sum of each quantity times its price, divided by the sum of the quantities. It is a weighted average, so a larger second entry pulls the average further toward its price than an equal-sized one would. Fees are separate and push the true break-even slightly beyond the average entry.
Does averaging down reduce my risk?
It reduces the price the position needs to reach in order to break even, which is what people mean when they say it helps. It also increases the size of the position while the original idea is still unconfirmed, so the same further adverse move now costs more. Both effects are real and they point in opposite directions — the calculator shows them side by side for that reason.
Why is the break-even price above my average entry?
Fees. You paid to enter and will pay to exit, both charged on notional, so the position has to move slightly beyond the average cost before closing it returns what you put in. The gap is small on a single trade and worth including when the intended move is also small.
What should I compare the result against?
The "move needed if you had not added" row. That is the counterfactual: what the original position alone would have required. Comparing the two makes the decision explicit — you are trading a smaller required recovery for a larger position, and the question is whether the idea is more likely to be right now than it was at the first entry.