Direct Answer
Bill Williams' Alligator plots three smoothed moving averages of the median price, each shifted forward: the jaw (13 periods shifted 8 bars), teeth (8 periods shifted 5) and lips (5 periods shifted 3). Their ordering and spacing are read as trend phases. When the three lines are intertwined the market is described as sleeping, with no clear trend.
Williams Alligator: Formula, Meaning, Signals, Examples and How to Use It
How Is Williams Alligator Calculated?
Bill Williams' Alligator plots three smoothed moving averages of the median price, each shifted forward: the jaw (13 periods shifted 8 bars), teeth (8 periods shifted 5) and lips (5 periods shifted 3). Their ordering and spacing are read as trend phases.
Formula: Jaw = SMMA(Median, 13) shifted 8; Teeth = SMMA(Median, 8) shifted 5; Lips = SMMA(Median, 5) shifted 3; Median = (High + Low) / 2
Inputs:
- High and low prices to form the median price
- Smoothed moving average (SMMA) periods 13, 8 and 5
- Forward shifts of 8, 5 and 3 bars
Worked example. For the 13-period jaw line, a prior value of 100 and a median price of 104 give an updated smoothed value of 100.308. The inputs are illustrative numbers, not market data.
Reading it. When the three lines are intertwined the market is described as sleeping, with no clear trend. When they spread out with lips on top, teeth in the middle and jaw below, an uptrend is indicated, and the reverse order a downtrend.
Limits. The shifted smoothed lines lag price, and the open-close pattern of the lines is slow to appear. In ranges the lines tangle repeatedly, and reading them involves judgment.
What is Williams Alligator?
Bill Williams' Alligator plots three smoothed moving averages of the median price, each shifted forward: the jaw (13 periods shifted 8 bars), teeth (8 periods shifted 5) and lips (5 periods shifted 3). Their ordering and spacing are read as trend phases.
How to use Williams Alligator
When the three lines are intertwined the market is described as sleeping, with no clear trend. When they spread out with lips on top, teeth in the middle and jaw below, an uptrend is indicated, and the reverse order a downtrend. A reading alone is never a buy or sell signal; it needs context from price structure, volume, volatility and the broader market regime.
Strengths
- Three lines with different lengths and shifts show ordering and spacing, so convergence and separation can be read on one chart.
- Using the median price makes the lines depend on bar range rather than the close, which reduces the effect of a single closing print.
- Reproducible when the formula and data convention are fixed.
Weaknesses and limitations
- Forward shifts of 3, 5 and 8 bars display the lines ahead of their calculation point, so they appear to lead although they use past data.
- The periods 5, 8 and 13 are Fibonacci-style numbers chosen by convention, not derived from market data.
- Correlated indicators can create false confidence by repeating the same underlying information.
Editorial and risk note
This page is educational content, not individualized investment advice. It should not imply guaranteed prediction, accuracy or outperformance.
Frequently Asked Questions
Is Williams Alligator a buy or sell signal?
No. When the three lines are intertwined the market is described as sleeping, with no clear trend. The shifted smoothed lines lag price, and the open-close pattern of the lines is slow to appear. A trade built on it still needs a trigger, an invalidation rule, a position size and realistic execution assumptions.
What is the best setting for Williams Alligator?
Williams Alligator takes these inputs: high and low prices to form the median price; smoothed moving average (SMMA) periods 13, 8 and 5; forward shifts of 8, 5 and 3 bars. There is no universal best setting for the tunable ones, so test them across instruments, regimes and out-of-sample periods and favor stable parameter regions over one historical winner.
Can Williams Alligator be used by itself?
The shifted smoothed lines lag price, and the open-close pattern of the lines is slow to appear. In ranges the lines tangle repeatedly, and reading them involves judgment. For that reason it is read next to measures of direction, participation, valuation, liquidity and risk, not alone.
Does Williams Alligator work on every timeframe?
The calculation (Jaw = SMMA(Median, 13) shifted 8; Teeth = SMMA(Median, 8) shifted 5; Lips = SMMA(Median, 5) shifted 3; Median = (High + Low) / 2) can be run on any bar size, but behavior is not portable: a reading on a five-minute chart describes a very different market window from the same reading on a daily chart. Validate the exact timeframe before relying on it.
Why does Williams Alligator give false signals?
Forward shifts of 3, 5 and 8 bars display the lines ahead of their calculation point, so they appear to lead although they use past data. The periods 5, 8 and 13 are Fibonacci-style numbers chosen by convention, not derived from market data. Lag, noise and regime changes add to this, because market participants react to new information after the reading is calculated.
How should Williams Alligator be backtested?
Rebuild Williams Alligator from high and low prices to form the median price using point-in-time data, write the rules before testing, include delisted securities where relevant, model realistic fills and costs, reserve a validation sample and compare with a simpler baseline.