What adding to a loser actually costs you

Averaging down is the most expensive habit in retail trading, and it is expensive precisely because the arithmetic feels good. Your average price improves. This shows you the number that gets worse at the same time.

First entry — shares

First entry — price

Your stop

Second entry — shares

Second entry — price

Account size

Your risk went from — to —.

Average price improves from — to —, so you now need a — move to get back to flat instead of —.

Position value is now —, or — of the account. If the stop still gets hit you lose — of the account rather than —.

The stop is treated as unchanged, which is the honest comparison. Moving the stop down to accommodate the second entry is a different decision and should be evaluated as one.

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The trade that feels free

Averaging down is seductive because two true things happen at once and only one of them is visible. Your average price falls, and the move needed to get back to flat gets smaller. That feels like progress and it is real.

What is not on screen is that your risk went up — often by a lot. If the stop was correct the first time, it is still correct, and now more shares are sitting behind it. In the default example above, the average price improves by a modest amount while the loss at the stop grows by more than half.

When it is a plan and when it is a reaction

This is a scale-in	This is averaging down
The second entry was decided before the first, at a defined level.	The second entry was decided because the position was red.
Total risk across both entries was sized so the full position still fits the risk rule.	The first entry was already full size; the second doubled it.
The stop is unchanged and was always below both entries.	The stop moved down to make room.
The thesis is intact — price reached a level you expected.	The thesis has quietly become "it has to come back".

The arithmetic is identical in both cases. The difference is entirely whether the number was chosen in advance, which is why writing the plan down before the entry is not a personality trait but a mechanism.

The part that ends accounts

Averaging down works until once. The distribution of outcomes is a long run of small recoveries that reinforce the habit, followed by a single position that keeps going and takes a multiple of what any of the recoveries returned. Because the habit was rewarded repeatedly, size tends to be at its largest exactly when it fails.

This is also why it does not show up in a win rate. The win rate looks excellent right up until the trade that matters.

Common questions

Is averaging down always wrong?

No — planned scale-ins are a legitimate and widely used approach, and long-term investors add to positions on weakness by design. What the calculator is for is making sure you are looking at the risk number and not just the average price, and that the total still fits the rule you set. Use the position size calculator on the combined position and see whether it still passes.

What if I move the stop down as well?

Then run it again with the new stop, and look at what the loss becomes. That is the honest version of the decision. What you should not do is compare the new average price against the old stop, which is the comparison that makes it look painless.

Is anything stored?

No. No server call, no cookie, no storage. Nothing you type here goes anywhere.

This is arithmetic, not advice. The calculator applies a standard, publicly known formula to numbers you type in. It does not know your circumstances, does not judge whether a trade is a good idea, and nothing you enter is stored or sent anywhere — it runs entirely in your browser. Educational purposes only. Not investment advice.

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The rest of the set

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Position size Account size, stop distance and risk percent in. Share count out. Risk per trade What one percent of your account actually is, in dollars, per trade and per day. R-multiple Turn an entry, stop and exit into an R number so trades of different sizes compare. Break-even The win rate a given reward-to-risk ratio needs before it makes money.