Williams %R: An Inverted, Rescaled Stochastic

Key Takeaways

• Williams %R equals minus the percentage distance from the current close to the highest high, divided by the window range.
• Standard 14-period readings above minus 20 mean overbought; readings below minus 80 mean oversold.
• Investors who flip on every overbought print miss that strong trends can pin %R above minus 20 for weeks.
• A cross above minus 50 after an oversold reading confirms upturn; below minus 50 after overbought confirms downturn.

What It Is

Williams %R is a bounded momentum indicator scaled from 0 to negative 100. A reading of 0 means the close equals the highest high of the lookback period. A reading of negative 100 means the close equals the lowest low. The default lookback is 14 bars.

The negative scale is a quirk of Larry Williams' original definition. Many platforms plot it on a flipped axis so it visually moves like a stochastic, but the underlying numbers still carry the negative sign.

The Intuition

Williams wanted a single number that captured "where is today's close inside the recent trading range?" If the close is at the top of the range, momentum is strong; at the bottom, weak. He chose to anchor the calculation to the highest high rather than the lowest low, which produced the negative scale.

The inverse-but-equivalent relationship to fast %K means anything you know about the stochastic oscillator transfers directly to Williams %R, after flipping the sign. A %K of 75 equals a Williams %R of negative 25.

How It Works

The Williams %R formula is:

%R = (HighestHigh_N - Close) / (HighestHigh_N - LowestLow_N) * -100

HighestHigh_N is the highest high of the last N bars; LowestLow_N is the lowest low. The default N is 14.

The signal conventions Larry Williams suggested:

• Above minus 20: overbought zone, watch for weakening momentum
• Below minus 80: oversold zone, watch for strengthening momentum
• Crossing minus 50 from below: confirms upturn after an oversold dip
• Crossing minus 50 from above: confirms downturn after an overbought spike

Williams %R is unsmoothed by default. Some platforms allow a 3-period moving average overlay for confirmation, similar to %D on the stochastic oscillator.

Worked Example

A stock over the last 14 trading days has:

• Highest high: 110.00 dollars
• Lowest low: 100.00 dollars
• Today's close: 108.00 dollars

Williams %R is:

%R = (110 - 108) / (110 - 100) * -100 = (2 / 10) * -100 = -20

The close is 2 dollars below the recent high inside a 10-dollar range, so %R reads exactly negative 20. That sits right at the overbought threshold. If price rallies another dollar to 109, %R becomes negative 10 and clearly overbought.

The next bar drops to 104, recalculate: (110 - 104) / (110 - 100) * -100 = -60. The 4-dollar pullback pushed %R from negative 20 to negative 60 in a single bar. That sharp drop after an overbought reading is the classic Williams sell trigger, especially when paired with a cross below minus 50.

Common Mistakes

1. Flipping on every overbought print. During a strong uptrend, %R can sit between minus 20 and 0 for many bars. Use a trend filter and wait for the cross back through minus 50 before acting.
2. Treating the negative scale as a different indicator. Williams %R is the fast stochastic %K with the sign flipped. Anything that fails for one fails for the other in the same conditions.
3. Ignoring divergences. Higher highs in price paired with lower highs in %R warn of weakening momentum. Many users only watch the threshold crossings.
4. Using too short a lookback. A 5-bar Williams %R fires constantly. The 14-bar default exists for a reason; shorter windows usually require additional smoothing.
5. Forgetting it is range-bound. %R cannot rise above 0 or fall below minus 100. Extended readings near either boundary signal continuation of the move, not exhaustion.

Frequently Asked Questions

What is the Williams %R indicator in simple terms? Williams %R measures how far today's close sits below the highest high of the last 14 bars, expressed on a scale from 0 to negative 100. Near 0 means the close is near recent highs; near negative 100 means it is near recent lows.

How does the Williams %R indicator affect investment decisions? Many traders look for the line to swing out of overbought (above minus 20) or oversold (below minus 80) zones and then cross minus 50 as confirmation of a trend change. The indicator works best paired with a trend or volume filter.

What is a real-world example of Williams %R? On a stock that rallies from 100 to 110 over two weeks, the 14-day Williams %R sits between minus 20 and 0 for most of the run. When price pulls back to 104, %R drops to negative 60 in one or two bars, marking the loss of upside momentum.

How can investors use Williams %R effectively? Stick to the 14-bar default and treat readings between minus 80 and minus 20 as range conditions. Act on crossbacks through minus 50 after an extreme reading, and confirm with price structure such as a lower high or lower low.

How is Williams %R different from the stochastic oscillator? Williams %R is mathematically the inverse of the fast stochastic %K. If %K reads 75, %R reads negative 25. The two indicators carry the same information; they differ only in scale orientation and default smoothing.

Sources

1. StockCharts ChartSchool. Williams %R. https://chartschool.stockcharts.com/table-of-contents/technical-indicators-and-overlays/technical-indicators/williams-r
2. Fidelity Learning Center. Williams %R. https://www.fidelity.com/learning-center/trading-investing/technical-analysis/technical-indicator-guide/williams-r
3. Incredible Charts. Williams %R. https://www.incrediblecharts.com/indicators/williams_percent_r.php
4. TradingView. Williams %R. https://www.tradingview.com/support/solutions/43000501985-williams-r-r/

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.