Drag the Gator Oscillator onto a chart and it doesn’t look like it wants to be read. Two rows of colored bars stack above and below a zero line, red and green flicker with no obvious rhythm, and there is no arrow anywhere. Bill Williams built it as a companion to his Alligator indicator, and the two together answer a question that most single-tool oscillators politely dodge: not which way the market is going, but how hard it is pulling.
By the end of this guide you will know what each histogram is measuring, how the four phases run as one continuous cycle, and the single check that stops you acting on a green bar before its candle has settled.
Key Findings
- Two histograms, one comparison: the upper bar plots the absolute distance between the Alligator's jaw and teeth, the lower bar plots the distance between the teeth and lips.
- Four phases in a cycle: Sleeping, Awakening, Eating and Sated run in sequence, and each phase tells you what the next one is likely to be.
- Companion, not replacement: the Gator measures strength but has no direction of its own, so it belongs under the Alligator, never in place of it.
- Repaint check: closed bars are locked; only the current, unfinished candle keeps updating, so a fresh green bar seen mid-candle can shrink or flip red before the close.
What is the Gator Oscillator?
The Gator Oscillator is a two-sided histogram that turns the Alligator’s three moving averages into a single measure of trend strength. Bill Williams introduced it as a companion to the Alligator, first in his 1995 book Trading Chaos and then in more detail in New Trading Dimensions (1998), and it exists to answer one narrow question: how wide is the Alligator’s mouth opening or closing on this bar?
It answers with two rows of bars, one that grows above the zero line and one that grows below it.
- The upper histogram plots the absolute distance between the jaw (the slow line) and the teeth (the middle line).
- The lower histogram plots the absolute distance between the teeth and the lips (the fast line).
Both distances are plotted as absolutes, so a bar always sits on its designated side of zero. The color is what carries the story. A bar is green when it is longer than the bar before it, and red when it is shorter. That color rule is doing more work than most new users realise; a red bar in the middle of a strong trend is not a signal to exit, it is a note that the current bar’s spread is a little tighter than the last one.
What are the four phases of the Gator Oscillator?
Williams named four states, and they map to the same feeding-alligator metaphor as the parent indicator. Read them as a sequence.
- Sleeping. Both histograms are tiny and both bars are red. The moving averages are braided together, the mouth is closed and price is going nowhere. Trend traders wait through this phase and do not force a signal out of it.
- Awakening. One side is green, the other still red. The Alligator’s lines are starting to unbraid and the market is testing whether a real move is coming. This is the earliest hint, not a confirmed entry.
- Eating. Both histograms print green together, and both are extending outward. The three lines have fanned out cleanly, the mouth is open and a trend is feeding. Williams treated this as the phase to be in a position, not the phase to enter one.
- Sated. Both sides are still green, but they are shrinking, or one has flipped to red. The trend is losing pace, the Alligator’s mouth is starting to close and continuation trades become riskier the deeper this phase goes.
The value in watching all four is that each phase leads to the next. A green bar out of a sleeping stretch tells you the market may be waking up. A red bar in the middle of an eating phase tells you the meal may be nearly over. You are reading a cycle, not chasing a threshold.
How do you read the Gator Oscillator?
Read the two histograms together, and treat color as the story. A single tall green bar on the upper side means nothing on its own. What matters is what the bar below it is doing at the same instant, and what the two of them did on the previous bar.
Start with the phase. Are both histograms tiny and red? You are in a sleeping market, and there is no trend to catch. Are both sides green and pushing out from zero? A trend is feeding, and continuation trades that agree with the direction of the Alligator’s lines are the ones to size normally. Are one or both bars shrinking after a run of green? The move is tiring, and this is the point to tighten a stop rather than add to a winner.
The oscillator does not tell you direction. That matters. It measures how wide the Alligator’s mouth is, but not which way that mouth is pointing, so you always read it with the Alligator on the chart above it. The Alligator gives you long or short ; the Gator gives you strong or weak.
Gator Oscillator vs the Alligator: which does what?
Traders often ask which of Williams’ two tools they should keep on the chart, as if it were a choice. It is not. They are two views of the same information and each answers a question the other cannot.
| Factor | Gator Oscillator | Alligator |
|---|---|---|
| Format | Two histograms above and below zero | Three lines on price |
| Reads | Trend strength, phase of the cycle | Trend direction, range vs trend |
| Answers | How wide is the mouth? | Which way is it pointing? |
| Best use | Confirm the current phase | Confirm direction of the setup |
| Weakness | No direction information | No clean strength read alone |
If you already run the Alligator, adding the Gator underneath it costs you nothing and closes the gap the Alligator by itself leaves: knowing whether the mouth is opening hard enough to trust. If you don’t run the Alligator, the Gator on its own is a dial without a compass.
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Get RelicusRoad ProWhere does the Gator Oscillator mislead you?
The honest weaknesses come from what the tool is, not what it fails to do. Two of them matter most.
First, the histogram is a derivative of a derivative. The bars measure the distance between smoothed moving averages, and smoothed averages lag price. In a sharp reversal the mouth can still read Eating for several bars after price has already turned, because the lines take time to close back together. Trusting a green bar in isolation gets you long right as the trend ends.
Second, color is memory. A bar is red only because it is shorter than the last one, not because the market has weakened in absolute terms. During a strong trend you will see occasional red bars in the middle of an eating phase without the trend being over. Reading a single red bar as a signal to exit misreads what color actually means.
That gap between “the signal fired” and “the trade was right” is why no oscillator, however elegantly built, replaces a full framework. It is the same point the Awesome Oscillator guide makes about Williams’ momentum tool: the picture sharpens timing, it does not create edge on its own.
Does the Gator Oscillator repaint?
Closed bars on the Gator Oscillator do not move. The three Alligator moving averages that feed it lock the moment a candle closes, and the two distances the histograms measure lock with them, so reloading the chart a week later shows the old bars sitting where you left them, in the same colors.
The live bar is where new users get caught. While the current candle is still trading, its close keeps moving, so both smoothed averages keep drifting, and both histogram bars keep updating tick by tick. A green bar that looks confirmed halfway through a candle can shrink, or flip red, by the time that candle closes. The rule is the one that steadies any oscillator: the reading you act on is the reading at the close, not the one you saw a minute earlier. The non-repaint forex indicator guide sets out the test that separates a genuine repaint from this normal live-bar recalculation.
Where does a phase-confirmed signal fit?
Reading Bill Williams’ pair by hand is a discipline. Watching the Alligator for direction, the Gator Oscillator for strength, and remembering not to trust either until the candle closes takes attention that most retail traders don’t have to spare mid-session.
RelicusRoad Pro folds that phase discipline into its trend read. It waits for the bar to close before committing a strength change, then weighs that confirmed reading against structure and momentum instead of firing on the flip of a single histogram bar. What it will not do is manufacture an edge you don’t have. If the market is sleeping, no tool can wake it up for you. The point is narrower and more useful: when the mouth does open, the signal you act on is the one that actually printed, not the one that shrank back before the close.
Frequently asked questions
What is the Gator Oscillator? The Gator Oscillator is a two-sided histogram introduced by the American trader Bill Williams as a companion to his Alligator indicator. The upper bar plots the absolute distance between the Alligator’s jaw and its teeth, the lower bar plots the absolute distance between its teeth and its lips, and the color of each bar changes with whether the distance grew or shrank compared with the previous bar. It exists to quantify trend strength, not direction, which is the piece the Alligator on its own leaves out.
What are the four phases of the Gator Oscillator? Williams described four sequential phases. Sleeping is both sides tiny and red, meaning the market is ranging and the Alligator’s lines are braided. Awakening is one side green and the other still red, an early hint that the mouth may open. Eating is both sides green and growing, meaning a trend is feeding. Sated is both sides shrinking, or turning red, meaning the trend is losing pace. The phases run in order and each one sets up the next.
Does the Gator Oscillator repaint? The Gator Oscillator does not repaint its closed bars. Because the three moving averages that feed it lock the moment a candle closes, the two histograms lock as well, and old bars stay where they printed when you reload the chart. The live bar is the exception. While the current candle is still trading, both smoothed averages keep updating tick by tick, so a fresh green bar seen mid-candle can shrink or flip red before the close. That is normal recalculation rather than a redraw of history.
What is the difference between the Gator Oscillator and the Alligator? The Alligator is three moving averages plotted directly on price, and it tells you trend direction and whether the market is ranging or trending. The Gator Oscillator is a pair of histograms plotted underneath price, and it measures the distance between those three lines to tell you how strong the trend is at each bar. The Alligator answers which way the market is going, the Gator answers how much conviction is behind the move.
Who created the Gator Oscillator? The Gator Oscillator was created by the American trader and author Bill Williams as a companion to his Alligator indicator. It appeared alongside the Alligator in his 1995 book Trading Chaos, and he laid out the four-phase cycle in more detail in New Trading Dimensions (1998), where he framed the two tools as a single reading system rather than separate signals.
The Gator Oscillator does not call the market for you. Read it against the Alligator, wait for the bar to close, and treat color as a story about strength rather than a buy signal on its own.
See how RelicusRoad Pro folds trend strength into one confirmed read →