Fibonacci Fans and Arcs

Straight trendlines are rigid. Fibonacci fans and arcs bend with the market.

While retracements and extensions work on horizontal price levels, Fibonacci fans and arcs project diagonal lines and curves from a major pivot. These tools combine price and time into dynamic support and resistance that adapts as the move develops — useful for trending markets where static levels fall behind.

Fibonacci fans

A Fibonacci fan is drawn from a significant swing high or low. The tool projects a series of diagonal lines (the "fan") at Fibonacci-based angles, typically derived from the vertical price move and the horizontal time elapsed.

The standard fan lines correspond to the ratios 0.382, 0.500, and 0.618 (and sometimes 0.236 and 0.764). In an uptrend drawn from a swing low:

• The 0.382 line is the steepest — represents strong trend support.
• The 0.500 line is moderate.
• The 0.618 line is the shallowest — the last line of defense before the trend is broken.

Reading the fan

• Price above the 0.382 line: strong uptrend intact.
• Price between 0.382 and 0.618: trend weakening, but support holding.
• Price below the 0.618 line: trend broken, reversal likely.

When price pulls back to a fan line and reverses, that line acts as dynamic support. A break below a fan line often targets the next lower line.

Fibonacci arcs

Fibonacci arcs are semicircles drawn from a significant pivot, with radii at the Fibonacci ratios 0.382, 0.500, and 0.618 of the price move. As time passes, the arcs curve — combining both price and time in a single line.

Arcs act as dynamic support in an uptrend (drawn from a swing low) and dynamic resistance in a downtrend (drawn from a swing high). Where price meets an arc, a reaction is more probable.

How fans and arcs differ

Tool	Shape	What it measures
Fan	Straight diagonal lines	Angular support/resistance
Arc	Curved lines	Price and time together

Fans are easier to read but rigid in angle. Arcs are harder to read but adapt their curvature to the time elapsed, making them more dynamic.

Drawing and trading them

Anchor either tool at a major swing pivot and drag to the swing's opposite extreme. The tool projects 0.382, 0.500, and 0.618 lines or arcs forward. Entry: as price pulls back to a line/arc and prints a reversal bar, enter with the trend. Stop: just beyond the line being tested. Targets: the prior swing high or a Fibonacci extension.

Both tools are dynamic and trend-following, but have limits: results depend on the chosen pivot (use the most significant swing), they generate noise in choppy ranges, and daily/weekly timeframes are more reliable than intraday.

Combining with other tools

Fans and arcs are most powerful when they coincide with horizontal Fibonacci levels. A 0.618 fan line crossing a 0.618 horizontal retracement creates a confluence — a high-probability reaction point where two independent Fibonacci measurements agree.

The honest edge

Fans and arcs are visual tools; their value is in highlighting dynamic support and resistance that static levels miss. Use them as a complement to retracements and extensions, not a replacement. A trader who combines horizontal Fibonacci levels with fan/arc confluence has a more complete picture of where the market is likely to react.

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Next: combining Fibonacci with Elliott Wave theory.