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Harmonics: use ratios as checkpoints
A beautiful XABCD drawing can still be a poor trade. Check the measurements and the response.
Understand ratio-based pattern filters without treating a reversal zone as a guaranteed turn.
Harmonic frameworks label successive swingsX,A,B,C,D and compare retracements or extensions. Different named patterns use different ratio requirements.
For the Gartley formulation described by Scott Carney, B is associated with 0.618 ofXA and D with 0.786 ofXA. These are checkpoints within a fuller pattern definition, not sufficient tests by themselves.
Fix swing-selection rules and tolerances first. Otherwise a chart offers enough possible anchors to create a convincing pattern after almost any reversal.
A potential reversal zone is a place to study response, not proof of reversal. Entry confirmation, invalidation, distance to the target and costs remain separate.
Let’s work through it
- Fix the swing anchors
- Check every required ratio
- Wait for a defined response
Let’s use numbers · hypothetical example
LetX=100,A=120. A 0.618 retracement fromA givesB=107.64; a 0.786 retracement givesD=104.28. These two values alone do not confirm a complete Gartley: the intervening legs and other conditions still need checks.
Easy mistakes to watch for
- Two ratios prove the pattern
- Adjusting anchors to fit
- A reversal zone guarantees reversal
Keep in mind
Small anchor changes can materially change ratios. Do not add extra risk simply because several ratios cluster.
Your turn
Calculate B and D forXA=20. Then change the swing anchors and explain why the same drawing may stop qualifying.
A quick check before we move on
ForX 100,A 120, where is the 0.786 retracement fromA?
- 115.72
- 105.72
- 104.28
Check answer
104.28 The leg is 20;20×0.786=15.72. Subtract from 120 to obtain 104.28.
Sources and further reading
Content reviewed: 29 October 2026
Educational material with hypothetical examples. Trading can cause substantial losses. A course, pattern, stop order or past result cannot guarantee a profit or limit every loss. Practise in simulation and check current rules and product terms in your jurisdiction.
