Williams %R Indicator

The Williams %R (Williams Percent Range) is a momentum oscillator that measures where the current closing price sits within the highest high and lowest low of a lookback period. Priced between 0 and −100, it identifies overbought and oversold conditions in equities and commodities.

What the %R measures

Williams %R is the inverse of the stochastic oscillator — same concept, inverted scale. It calculates:

%R = −100 × (Highest High − Close) / (Highest High − Lowest Low)

Over a typical 14-bar window, if price closes at the highest high, %R = 0. If it closes at the lowest low, %R = −100. Mid-range closes register between these poles. The inversion (0 to −100 rather than 0 to 100) was Williams’ choice; both forms track identical momentum.

Why traders use extremes to time entries

When %R approaches −20, the close has compressed into the upper band — signal of overbought price. Many traders treat this as a warning flag for potential pullback or short entry. Conversely, %R below −80 signals oversold conditions, where mean reversion trades expect a snap-back higher.

The key assumption: extreme closes relative to recent range reflect temporary excess, not sustainable trend. A stock that touches −20 within minutes may reverse by day’s end; one stuck above −30 for a week suggests trend strength and breaks the overbought signal. Context matters.

Comparison to stochastic

Stochastic oscillators and Williams %R are near-identical mechanics — Larry Williams designed %R partly in response to stochastic criticism. Both use a 14-period high-low range. The practical difference:

• Stochastic adds a smoothed moving average (K-line and D-line), which filters noise but lags signal.
• Williams %R is the raw calculation, more reactive but noisier.

Traders choose based on tolerance for false signals. Slower stochastic suits swing traders holding days or weeks; raw Williams %R works for intraday scalpers.

When %R fails to predict reversals

Pure overbought-oversold signals are unreliable in strong uptrends or downtrends. During a sustained rally, a stock may stay above −30 for weeks while continuing to climb — the “overbought” label masks accelerating momentum. Similarly, in washouts, oversold reads persist as price plummets further.

This blind spot is why skilled traders use Williams %R in combination with trend confirmation. A −80 read in a downtrend is less trustworthy than a −80 read after a sharp intraday spike following a calm period. Price action, volume, and broader market context are the filters.

Interpretation across timeframes

A 14-bar Williams %R on a daily chart captures extreme closes within the last ~2–3 weeks of trading. The same instrument on a 1-minute chart captures ~14 minutes of price action. This matters: a −20 reading on the minute chart is not the same as −20 on the daily. Intraday traders use shorter periods (5–10 bars); swing and position traders use 14–21 bars.

Practical use in entry and exit logic

Many traders weave Williams %R into decision rules:

• Entry trigger: Buy at %R = −80 after a multi-day sell-off in an otherwise healthy stock, on the assumption of quick mean-reversion bounce.
• Exit signal: Close a long position when %R climbs above −20, locking gains ahead of potential pullback.
• Confirmation: Cross %R below −50 in alignment with a confirmed support-level break signals conviction in the downmove, not just a spike.

The weakness: mechanical rules (buy every −80, sell every −20) routinely trigger false signals. Markets reward traders who use the oscillator as a prompt to look closer, not a self-contained system.

Divergence spotting

When price makes a new high but %R fails to reach −20 (or new low but %R stays above −80), the indicator signals waning momentum — a divergence pattern many technicians track. This can precede a trend reversal, especially if confirmed by other signals like decreasing volume or a failed breakout.