The levels
Measure a swing from low to high, then mark the fractions of it where price might pull back:
uptrend: level = high − (high − low) × ratio
downtrend: level = low + (high − low) × ratio
| Ratio | Where it comes from |
|---|---|
| 23.6% | Fibonacci sequence |
| 38.2% | Fibonacci sequence |
| 50% | not Fibonacci — convention |
| 61.8% | the golden ratio |
| 78.6% | square root of 61.8% |
Extensions project beyond the swing: 127.2% and 161.8% are the two in common use as targets.
The 50% level, stated plainly
It is not a Fibonacci ratio. It is not in the sequence, it is not derived from the golden ratio, and it is on virtually every chart.
It is there because price frequently retraces about half of a move, which was observed long before anyone attached Fibonacci to charts — Dow theory describes the same tendency. It survives because it is often the most useful line on the drawing.
Presenting it silently among the real ratios implies a mathematical pedigree it does not have. It is more honest, and more useful, to know that one of the five lines is a rule of thumb wearing the same clothes as the other four.
What these levels actually are
There is no mechanism by which the golden ratio governs markets. What exists is a very large number of traders drawing the same tool between roughly the same two points, and placing orders at the resulting lines.
That makes Fibonacci levels a coordination device: they work to the extent that they are widely watched, in the same way pivot points do. It is a real effect and a modest one, and it decays wherever the swing being measured is ambiguous.
Which is often. The tool requires choosing a high and a low, and reasonable people choose differently — a different timeframe, a different wick, a different starting swing. Levels drawn from a different swing are different levels, and this is why Fibonacci analysis looks so persuasive in hindsight: with several plausible swings, some line always sits near the turn.
Using them without fooling yourself
Three habits make the difference:
- Choose the swing before the outcome. Draw it on the most recent obvious high and low, and do not redraw it because price ignored the first attempt.
- Use levels as places, not as signals. A level is somewhere to look for a reason to act, not the reason itself.
- Put the stop beyond the structure, not beyond the level. A stop just past 61.8% is where every other Fibonacci trader also put theirs, which makes it a liquidity pool rather than protection.