Fair value gap: what it is, and how to draw it
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The short answer
A fair value gap is a hole left behind by a move that was too fast. It is read across three consecutive candles: when price rises quickly, the low of the third candle stays above the high of the first, and the space between those two levels is the gap. When price falls quickly, it is the mirror image. Unlike most Smart Money Concepts markers, this one is measured without interpretation: the rule is arithmetic, and two people applying it find exactly the same zone.
The three-candle rule
Look at three consecutive candles in the middle of a decisive move. In the bullish case, compare the highest point of the first candle with the lowest point of the third. If a space remains between them, meaning the low of the third sits above the high of the first, that space is a fair value gap. The bearish case is symmetrical: the high of the third stays below the low of the first.
The middle candle plays no part in the calculation, it is the move itself. Its neighbours are what bound the hole.
That mechanical precision is what sets the fair value gap apart from most of the Smart Money Concepts vocabulary. An order block requires judging whether a move was decisive enough to count; a fair value gap does not. Two people applying the rule to the same chart get the same zone, in the same place, at the same levels. That is rare in this field, and it is why this marker is the easiest one to automate honestly.
Why the hole is interesting
On a market moving calmly, every price level is crossed slowly and everyone has time to position themselves. A fair value gap says the exact opposite: price went through that slice so fast that trading there was thin, or absent on one side of the book entirely.
From that comes the widespread idea that price tends to come back and fill the hole, rebalancing what was left unbalanced. It is an empirical observation, not a law: it often holds, it does not always hold, and no mechanism obliges the market to return. Anyone presenting that return as a certainty is selling something.
There is a useful nuance behind the idea. A gap left during a strong acceleration in the direction of the trend is not the same animal as a gap left by an isolated candle on a Sunday evening. The first describes an imbalance, the second mostly describes a lack of participants.
Filled, half filled, never touched
A fair value gap meets one of three fates, and telling them apart saves you from the wrong conclusion:
- it is fully filled, price traded back through the whole zone;
- it is partly filled, often as far as its midpoint, and then the move resumes;
- it is never touched at all, and sits on the chart producing nothing.
The midpoint of the zone holds a special place in common practice, many traders treating a return that far as enough to call it rebalanced. That is a widespread habit, not a rule: here too there is no authority to settle it, and you will find different readings depending on the source.
The third case deserves to be said plainly, because it is systematically missing from enthusiastic write-ups: a substantial share of gaps are never revisited. Building a plan on the assumption of a return, without asking what you do if it never comes, is a way of waiting for an entry that will not arrive.
How it differs from an order block
The two get confused constantly, for an understandable reason: they often overlap. They do not measure the same thing.
A fair value gap is a measurement. Three candles, two levels, a space in between. There is nothing to interpret, only to compute.
An order block is a role assigned to a candle. You point at the one the move departed from, which requires judging that the move mattered. A share of interpretation is unavoidable.
The overlap comes from the fact that they describe the two ends of the same event: the order block sits at the origin of the move, the fair value gap in its wake. When price comes back to a zone where both coincide, two independent readings point at the same spot, and that is exactly why those zones draw more attention.
What it does not tell you
A fair value gap gives neither direction nor timing. It bounds a zone; it does not say whether price will return to it, or when, or what it will do on arrival.
Nor does it stand on its own. A gap taken in isolation, without knowing what the higher timeframes are saying, marks a space on a chart and nothing more. The vocabulary you need to place it in context is gathered in our Smart Money Concepts glossary.
Finally, the precision of the rule does not guarantee the relevance of the result. You can compute a useless marker perfectly on a given market, and trading carries a risk of capital loss that the rigour of a definition does not reduce.
How AlphaGPT computes them
The three-candle rule is applied as written, across several timeframes at once, with the same thresholds on every analysis. Since the calculation leaves no room for judgement, two analyses of the same chart at the same moment return exactly the same gaps.
Each zone is dated and its state tracked, so a gap already traded through is not presented as fresh. It is then cross-checked against structure and against the zones described on our order block page, because an isolated marker is not worth much.
What you get is not an annotated picture but a numbered plan, with an entry, a stop, targets and a position size matched to your risk.