Direct Answer
Harmonic chart patterns are a family of price patterns built on five labeled swing points, X, A, B, C, and D, where the length of each leg is expected to relate to another leg by a Fibonacci retracement or extension ratio. The approach, associated with harmonic-trading methodology, uses named patterns such as the Gartley, Butterfly, Bat, and Crab to project a Potential Reversal Zone, or PRZ, where the D point is likely to complete and price may turn.
Key Takeaways
- Every harmonic pattern is built from five swing points labeled X, A, B, C, and D, connected by four legs: XA, AB, BC, and CD.
- Each named pattern, Gartley, Butterfly, Bat, Crab, Deep Crab, Shark, Cypher, and 5-0, is distinguished by roughly where its D point is expected to complete relative to the XA leg.
- The Potential Reversal Zone (PRZ) is the price area where several independent Fibonacci projections cluster, not a single exact number.
- Published ratio ranges vary across harmonic-trading sources, treat all figures here as commonly cited approximations, not a single verified standard.
- Every pattern has both a bullish and a bearish mirror-image version, and confirmation still depends on price action inside the PRZ, not on the ratio alone.
What Are Harmonic Patterns?
Harmonic patterns are a technical-analysis approach that labels five consecutive swing highs and lows X, A, B, C, and D, then checks whether the ratios between the resulting legs, XA, AB, BC, and CD, fall inside the approximate Fibonacci retracement or extension zones associated with a specific named pattern. The methodology is commonly associated with harmonic trading, most notably the work of Scott Carney, who is widely credited with formalizing and popularizing many of the patterns described below, though the broader use of Fibonacci ratios in technical analysis predates any single author.
The core building block is the Fibonacci ratio itself, numbers such as 0.382, 0.5, 0.618, 0.786, 1.27, and 1.618 that recur throughout retracement and extension analysis. A harmonic pattern doesn't use just one of these ratios; it requires a specific combination across multiple legs before a setup qualifies as, for example, a Gartley rather than a Bat.
Where those legs are projected to converge is called the Potential Reversal Zone, or PRZ. Because several independent Fibonacci projections, drawn from different legs of the pattern, are expected to cluster in the same general price area, that confluence is treated as a higher-confidence zone than any single ratio in isolation. Traders generally wait for price-action confirmation inside the PRZ, such as a reversal candle, a break of a short-term trendline, or a shift in momentum, rather than acting purely because price touched a calculated level.
A note on precision: the exact numeric ratio ranges cited for each pattern below vary somewhat across different harmonic-trading sources and authors. This page presents them as commonly cited approximate ranges, not as a single verified numeric standard, and rounds using language like "around" or "roughly" rather than false precision. Treat every ratio on this page as a guideline for where to look, not an exact trigger.
1. AB=CD Pattern
The AB=CD is the simplest harmonic pattern and the building block for the more complex XABCD patterns that follow. It starts with an initial leg, AB, then a corrective retracement, BC, that gives back part of AB, followed by a CD leg that is designed to be roughly equal in length to AB, often with a roughly similar time duration as well. The point where CD is projected to equal AB defines the setup's completion zone.
This is the harmonic-trading version of the same core idea behind the measured move pattern's projection technique, projecting a second leg to roughly match the length of a first leg. The harmonic AB=CD typically layers in a Fibonacci-ratio confirmation on the BC retracement, commonly cited as landing somewhere in the 0.382 to 0.786 range of AB, as an added filter that the simpler measured-move technique doesn't require.
2. Gartley Pattern
The Gartley is a five-point XABCD retracement pattern and one of the oldest named harmonic setups. Point B is commonly cited as retracing roughly 0.618 of the XA leg. Point C then retraces a portion of AB, and the CD leg projects out so that point D completes at roughly a 0.786 retracement of the overall XA leg. Because D stays inside the XA range rather than extending beyond point X, the Gartley is often described as a moderate, retracement-style completion.
3. Butterfly Pattern
The Butterfly shares the same XABCD skeleton as the Gartley, but with a key structural difference: point D extends beyond point X rather than staying inside the XA range. Point B is commonly cited as a deeper retracement of XA, often around 0.786, and point D is commonly cited as projecting to roughly a 1.27 to 1.618 extension of the XA leg. That extension beyond X is the defining trait that separates the Butterfly, and the other "extension" patterns below, from the Gartley and Bat.
4. Bat Pattern
The Bat pattern also completes inside the XA range, like the Gartley, but with a shallower B point. Point B is commonly cited as retracing roughly 0.382 to 0.5 of XA, noticeably shallower than the Gartley's deeper B point. Point D is commonly cited as completing at roughly a 0.886 retracement of XA, deeper than the Gartley's D point but still short of point X, unlike the Butterfly.
5. Crab Pattern
The Crab is known for one of the most extreme D-point extensions among the commonly cited harmonic patterns, with point D projecting well beyond point X. Its D point is commonly cited as completing at roughly a 1.618 extension of the XA leg, a deeper extension than the Butterfly's. Because the projected reversal zone sits so far beyond the original XA move, the Crab is often described as offering a favorable reward-to-risk setup when the PRZ does hold, precisely because the projected stop distance relative to the target can be tight.
6. Deep Crab Pattern
The Deep Crab is a variant of the Crab pattern that starts from a deeper B point. Point B is commonly cited as retracing roughly 0.886 of the XA leg, deeper than the standard Crab's B point, before the pattern follows a similar extreme CD extension to complete point D, commonly cited around the same roughly 1.618 extension of XA used for the standard Crab. The deeper starting retracement is the main structural difference between the two.
7. Shark Pattern
The Shark is a more recently popularized five-point pattern, sometimes labeled O-X-A-B-C instead of the classic XABCD naming, reflecting its somewhat different construction from the Gartley-family patterns above. Rather than being built primarily from retracement ratios the way the Gartley, Bat, and Butterfly are, the Shark's later leg into its completion point is generally described as extension-based. Because published numeric ranges for the Shark vary more across sources than for the older, more established patterns, this page describes its general shape and logic rather than citing a specific ratio it isn't confident is accurate.
8. Cypher Pattern
The Cypher is another XABCD-style pattern, but its BC leg is distinctive: it extends beyond the XA leg rather than staying within it, before the pattern completes at point C rather than following the more familiar D-point completion structure used by the Gartley-family patterns. That extension-beyond-XA behavior on the BC leg, rather than a purely retracement-based structure, is the Cypher's defining structural trait. As with the Shark, this page describes the pattern's general shape and logic rather than citing precise ratio figures it can't verify against a single consistent source.
9. 5-0 Pattern
The 5-0 is a continuation-style harmonic pattern, often described as building out of an extended XABC structure, sometimes starting from the B, C, and D points of a prior harmonic pattern that get relabeled as the new setup's starting points. It's generally described as completing near a 0.5 retracement of a preceding leg, which is the origin of the pattern's name. Because the exact construction rules published for the 5-0 vary more across sources than for the core Gartley-family patterns, this page describes its general continuation-style logic rather than citing additional precise ratios it isn't confident are consistent across sources.
10. Three Drives Pattern
The Three Drives pattern is built from three consecutive, roughly symmetrical price swings, or "drives," to new highs (bearish version) or new lows (bullish version), rather than the XABCD point labeling used by the patterns above. Each drive is commonly cited as relating to the prior drive by a similar Fibonacci extension ratio, often around 1.27 or 1.618, and each corrective retracement between drives is commonly cited as falling in a similar Fibonacci retracement zone, often around 0.618 to 0.786. The pattern's defining trait is that symmetry repeats across all three drives and both corrective pullbacks, rather than a single completion point.
The Potential Reversal Zone (PRZ)
Every pattern above ultimately points toward the same concept: a Potential Reversal Zone where multiple independently calculated Fibonacci levels, drawn from different legs of the pattern, cluster in roughly the same price area. The more independent projections that converge there, the more significance traders typically assign to that zone. A PRZ is a price area, not a single price, and it's a projection of where a reversal might occur, not a guarantee that one will.
Because the PRZ is a probabilistic zone rather than a precise trigger, most harmonic traders look for price-action confirmation once price enters it, a reversal candlestick, a break of a short-term trendline, a shift in momentum, or a matching signal from another indicator, before treating the pattern as validated. Acting the instant price touches a calculated ratio, without waiting for that confirmation, is one of the more common mistakes described below.
Harmonic Patterns Compared
All ten patterns share the XABCD (or, for the Shark and Three Drives, a related) point structure and the same underlying logic: legs related by Fibonacci ratios, converging on a Potential Reversal Zone. What differs is where D is projected to complete relative to the starting XA leg, and every pattern below has both a bullish and a bearish mirror-image version.
| Pattern | General D-point projection relative to XA | Bullish and bearish variants |
|---|---|---|
| AB=CD | Not XA-based; CD projects to roughly equal AB in length | Both exist |
| Gartley | Completes inside XA, commonly cited around a 0.786 retracement | Both exist |
| Butterfly | Extends beyond X, commonly cited around a 1.27-1.618 extension | Both exist |
| Bat | Completes inside XA, commonly cited around a 0.886 retracement | Both exist |
| Crab | Extends well beyond X, commonly cited around a 1.618 extension | Both exist |
| Deep Crab | Extends well beyond X, similar to Crab, from a deeper B point | Both exist |
| Shark | Extension-based completion; described conservatively, no confident precise figure cited | Both exist |
| Cypher | Completes at C after BC extends beyond XA; no confident precise figure cited | Both exist |
| 5-0 | Continuation-style, generally described near a 0.5 retracement | Both exist |
| Three Drives | Not XA-based; three symmetrical drives replace a single D point | Both exist |
How to Trade Harmonic Patterns
Because harmonic patterns rest on multiple Fibonacci ratios agreeing across several legs, most of the work is in the identification itself: measuring each leg, checking whether its ratio to the relevant prior leg falls inside the commonly cited range for the pattern being considered, and confirming that the resulting projections actually cluster into a coherent PRZ rather than scattering across a wide price band. A PRZ built from projections that barely overlap is weaker evidence than one where several independent levels land close together.
Once price reaches the PRZ, the standard approach is to wait for price-action confirmation, not to enter purely because a calculated ratio was touched. A stop is typically placed beyond the far edge of the PRZ or beyond point X, since a break past that level suggests the projected structure has failed rather than merely being tested. As with any pattern-based setup, position size should follow the account's standard risk-per-trade rules based on the distance to that invalidation point, not an arbitrary percentage.
Common Mistakes
- Treating any five-swing zigzag as a harmonic pattern without actually measuring whether the leg ratios fall inside the relevant commonly cited ranges.
- Entering the instant price touches a calculated PRZ level rather than waiting for price-action confirmation inside the zone.
- Citing a single ratio as if it were an exact, universally agreed number, when published ranges vary across harmonic-trading sources.
- Confusing similar patterns, for example mistaking a Bat's shallower B point for a Gartley's deeper one, which changes where the PRZ should actually be projected.
- Ignoring how tightly the pattern's independent Fibonacci projections actually cluster, and treating a wide, loosely overlapping zone the same as a tight, well-confirmed one.
Harmonic Pattern Checklist
- All five swing points (or three drives, for the Three Drives pattern) are clearly identifiable on the chart, not forced onto ambiguous price action.
- Each leg's ratio to the relevant prior leg falls inside the commonly cited range for the specific pattern being considered.
- Multiple independent Fibonacci projections actually cluster into a tight Potential Reversal Zone, rather than spreading across a wide price band.
- Price action inside the PRZ, not just the ratio touch itself, is used as the entry trigger.
- An invalidation level (beyond the PRZ or point X) is identified before entry, with position size set from that distance under standard risk-per-trade rules.
How Much Tolerance Turns a Ratio Into a Coincidence
Harmonic patterns are defined by ratio relationships between legs, and every practical implementation allows a tolerance around each ratio because exact values almost never occur. The size of that tolerance determines everything: tight, and the patterns are rare; loose, and they appear constantly by chance.
The honest way to use them is to fix the tolerance in advance and never widen it for a specific setup. Widening tolerance in the moment is how a pattern is found rather than identified, and once several ratios each carry generous tolerance, the combined probability of a random sequence qualifying becomes substantial.
The deeper issue is that these patterns do not come with a mechanism. There is no established reason why price should respect specific ratio relationships between swings, and the case for them rests on observed frequency, which is exactly the claim that generous tolerances make impossible to evaluate.
The pattern also depends on which swing highs and lows are chosen as the pivot points, and that choice varies with the timeframe examined and the smoothing applied. Two analysts identifying pivots differently produce different patterns from identical data, and neither has made an error.
Harmonic Patterns FAQs
What are harmonic chart patterns?
Harmonic chart patterns are a family of price patterns built on five labeled swing points, X, A, B, C, and D, where each leg's length is expected to relate to another leg by a Fibonacci retracement or extension ratio. The approach is associated with harmonic trading methodology and includes named patterns such as Gartley, Butterfly, Bat, and Crab.
What is the Potential Reversal Zone?
The Potential Reversal Zone, or PRZ, is the price area where a harmonic pattern's D point is projected to complete, formed where multiple Fibonacci retracement and extension levels cluster together. Traders watch for price-action confirmation inside the PRZ, such as a reversal candle or a break of short-term structure, rather than acting the instant price touches it.
Are harmonic pattern Fibonacci ratios exact?
No. Different sources in harmonic-trading literature publish slightly different approximate ranges for each pattern's ratios, and real price swings rarely land on a ratio precisely. The ratios commonly cited for patterns like the Gartley or Butterfly are best treated as approximate zones of confluence, not exact numeric triggers.
What is the difference between a Gartley, a Bat, and a Butterfly pattern?
All three share the same XABCD structure, but they differ in how far the AB leg retraces the XA leg and where the D point completes. The Gartley and Bat patterns complete inside the XA range, commonly cited around a 0.786 and 0.886 retracement respectively, while the Butterfly's D point extends beyond point X, commonly cited around a 1.27 to 1.618 extension.
Do harmonic patterns work in both directions?
Yes. Every harmonic pattern described here has a bullish and a bearish mirror-image version. A bullish version projects a D point that suggests a low is forming, and a bearish version projects a D point that suggests a high is forming; the same Fibonacci-ratio logic applies to both.
How much tolerance is acceptable on a harmonic pattern's Fibonacci ratios?
Practitioners commonly allow a few percent of deviation from the ideal ratios, since exact hits are rare on real price data. The problem this creates is that widening tolerance increases how many patterns are found, and a large enough tolerance finds patterns everywhere. Fixing the tolerance in advance and applying it consistently is what stops the method from becoming an exercise in finding shapes after the fact.
What is the difference between a harmonic pattern and an ordinary reversal pattern?
Ordinary reversal patterns are defined by structure, such as two equal highs or a head between two shoulders. Harmonic patterns are defined by the proportional relationships between swing lengths, so two patterns with the same visual shape can be different harmonic patterns depending on their ratios. This makes harmonic identification more mechanical and also more sensitive to exactly which swing highs and lows are selected.
How do you choose which swing points to use when building a harmonic pattern?
Swing selection is the main source of disagreement in harmonic analysis, because slightly different choices produce different ratios and therefore different pattern names. Using a defined swing-detection rule, such as a minimum percentage move or a fixed bar count, makes the selection reproducible. Choosing points by eye to make the ratios fit is the failure mode the method is most vulnerable to.
Do harmonic patterns require a specific stop placement?
Most descriptions place the stop beyond the pattern's terminal point, since a move past it means the proportional relationship the pattern relies on has broken. That level is determined by the pattern rather than chosen, which is one of the method's practical advantages. The tradeoff is that on a pattern spanning a wide range, the resulting stop distance can be large enough to make the position size very small.