Trading glossary
Swing high and swing low
By the PatternX team · Published
Definition
A swing high is a bar whose high is above the highs of the bars on either side of it, and a swing low is a bar whose low is below its neighbors' lows. Together they mark price's turning points.
Also called: pivot high, pivot low
How it's measured
The standard definition uses a window of w bars on each side. Bar i is a swing high when:
A swing low is the mirror image: the lowest low across the same window. With w = 2, a bar needs two lower highs on each side, the classic five-bar fractal. A larger window finds fewer, more significant turning points; a smaller one finds more, noisier ones.
The definition has a built-in delay. A swing high can't be confirmed until w bars after it have printed, because any of them could still exceed it. Pivots are therefore always known w bars late.
Why it matters
Swing points are the raw material of chart reading:
- A trend is a sequence of them: higher highs and higher lows in an uptrend, lower highs and lower lows in a downtrend.
- Support and resistance form where swings cluster.
- Trendlines and necklines connect them.
- Stops are commonly placed just beyond the most recent swing.
Example
For example, take five consecutive daily highs: $21.10, $21.60, $22.40, $22.00 and $21.70. With w = 2, the middle bar's $22.40 is the highest of the five, so it is a swing high, but you only know that once the fifth bar is complete. Had the fifth bar reached $22.50, $22.40 would not qualify.
Common mistakes
- Forgetting the lag. A pivot drawn on a live chart may not exist yet.
- Mixing window sizes. A 2-bar pivot and a 10-bar pivot describe different scales of movement.
- Counting every wiggle. On noisy, low timeframes, small windows produce many meaningless pivots.
How PatternX uses it
PatternX's detectors use this definition. The cup and handle, head and shoulders, and double and triple tops and bottoms use a 3-bar window, so their pivots are confirmed three bars late; triangles, wedges and rectangles use a 2-bar window, confirmed two bars late. Flags, pennants and rounding patterns are defined by other measurements, such as the pole or averaged price buckets. Stops often come from swings: the falling wedge uses its lowest swing low and the ascending triangle its latest higher low. In PatternX AI, the market-structure factor checks whether the last three swing highs and lows within 60 candles agree with the trade. See pattern detection.