Published on: 2023-11-08
Updated on: 2026-05-07
The William index is a simple momentum indicator, but many traders misuse it. A reading near overbought does not always mean price is ready to fall, and a reading near oversold does not always mean price is ready to rebound.
That distinction matters more in today’s markets. Gold’s powerful 2025 rally and AI-led equity momentum showed that strong assets can stay overbought for long periods. The William index, also known as Williams %R or WR, works best when traders use it to gauge momentum, not as a blind buy or sell signal.
The William index measures where the latest closing price sits inside a recent high-low range.
WR moves from 0 to -100, with 0 to -20 usually overbought and -80 to -100 usually oversold.
The default setting is 14 periods, but short-term traders often test 7, 9, 12 or 21 periods.
Overbought can show strong buying pressure, not just reversal risk.
The indicator works best with trend analysis, support and resistance, RSI, MACD or moving averages.
The William index is a technical analysis indicator created by Larry Williams. Its full name is Williams Per cent Range, often written as Williams %R or WR.
It compares the current closing price with the highest high and lowest low over a selected period. If the price closes near the top of that range, WR moves closer to 0. If the price closes near the bottom, WR moves closer to -100.
This makes the indicator useful for spotting short-term momentum extremes. It can help traders see when buying pressure is stretched, when selling pressure is exhausted, or when a market is still trading strongly inside a trend.
The formula is:
WR = [(Highest High - Close) / (Highest High - Lowest Low)] x -100
The “highest high” is the highest price reached during the chosen period. The “lowest low” is the lowest price during the same period. The close is the latest closing price.
For example, if gold has a 14-period high of $4,650, a 14-period low of $4,450 and a latest close of $4,610:
WR = [(4,650 - 4,610) / (4,650 - 4,450)] x -100 = -20
A WR reading of -20 means the price closed near the top of its recent range. That shows strong upward pressure. It may warn that the price is stretched, but it does not confirm a reversal on its own.
The two most important zones are -20 and -80.
When WR rises between 0 and -20, the market is usually considered overbought. This means the price is closing near the top of its recent range. In a sideways market, that may warn of a pullback. In a strong uptrend, it may simply confirm strong demand.
When WR falls between -80 and -100, the market is usually considered oversold. This means the price is closing near the bottom of its recent range. In a range-bound market, that may warn of a rebound. In a strong downtrend, it may confirm heavy selling pressure.
This is where many traders make mistakes. They sell only because WR reaches -20, or they buy only because WR reaches -80. That approach ignores trend direction.
A stronger method is to wait for price confirmation. For a bullish setup, traders often watch for WR to rise back above -80 while price holds support. For a bearish setup, traders may watch for WR to fall back below -20 while price rejects resistance.
The William index has four practical uses.
WR shows when the price is near the edge of its recent range. A reading near -10 signals strong buying pressure. A reading near -90 signals strong selling pressure. These readings help traders become more selective.
Divergence occurs when price and WR stop moving in sync. If price makes a higher high but WR forms a lower high, upside momentum may be weakening. If price makes a lower low but WR forms a higher low, selling pressure may be fading.
In an uptrend, a move toward -80 can mark a pullback rather than a sell signal. If price remains above a rising moving average and WR turns higher, traders may read it as renewed buying interest.
In a downtrend, a move toward -20 can mark a temporary rebound rather than a buy signal. If the price remains below the resistance and the WR turns lower, sellers may still control the market.
A daily chart can show the main trend, while a 1-hour or 4-hour chart can help refine timing. If the daily trend is bullish, short-term oversold readings may offer better entry zones. If the daily trend is bearish, short-term overbought readings may warn of failed rebounds.
There is no perfect William index setting. The best parameter depends on the market, volatility and trading style.
Shorter periods react faster but generate more false signals. Longer periods are slower but cleaner. For most traders, the 14-period setting remains the best starting point.
Accuracy does not come from one “best” number. It comes from matching the setting to the market.
In a quiet range, the standard -20 and -80 levels can work well because price often rotates between support and resistance. In a strong trend, those same levels can mislead traders, as WR may remain overbought or oversold for longer than expected.
A practical setup process is simple:
Start with 14 periods.
Use -20 and -80 as default zones.
Check whether signals arrive too early or too late.
Shorten the period for faster markets.
Lengthen the period for choppy markets.
Confirm signals with price structure.
The William index should not replace risk management. A valid trade still needs an entry trigger, an invalidation level and a position size that fits account risk.
The 42 and 12 method uses two WR lines. The 42-period line acts as the slower momentum guide. The 12-period line reacts faster to price changes.
The formula is the same for both:
WR12 = [(Highest High over 12 periods - Close) / (Highest High over 12 periods - Lowest Low over 12 periods)] x -100
WR42 = [(Highest High over 42 periods - Close) / (Highest High over 42 periods - Lowest Low over 42 periods)] x -100
A possible bullish signal appears when both lines are near oversold, WR12 turns above WR42, and price holds support. A possible bearish signal appears when both lines are near overbought, WR12 turns below WR42 and price fails at resistance.
This method should be treated as an early warning, not a complete stock-picking system. The cross matters more when it appears at a major technical level.
The first mistake is treating overbought as an automatic sell signal. In strong rallies, being overbought can confirm momentum.
The second mistake is treating oversold as an automatic buy signal. In heavy selloffs, oversold can confirm that sellers remain in control.
The third mistake is using WR without a market structure. The indicator is much stronger when it agrees with support, resistance, trend lines or moving averages.
The fourth mistake is ignoring news risk. During major economic releases, spreads can widen, and prices can move faster than an oscillator can confirm.
Yes. The William index usually refers to Williams %R, also called WR. It is a momentum oscillator that measures the latest close against the high-low range over a selected period.
The standard setting is 14 periods. Short-term traders may test 7, 9 or 12 periods, while swing traders may prefer 14, 21 or 42 periods. The best setting depends on the asset and time frame.
Yes, but only if beginners understand its limits. It is easy to read, but it can give false signals in strong trends. It should be used in conjunction with price action, trend direction, and risk control.
It can warn of stretched momentum, but it cannot predict reversals on its own. A stronger reversal signal appears when WR divergence forms near support or resistance, and price confirms the turn.
The William index remains useful because it provides traders with a quick view of momentum pressure. It shows whether the price is closing near the top or bottom of its recent range, which helps identify overbought and oversold conditions.
Its weakness is also clear. It can tempt traders to fight strong trends too early. The better approach is to use WR as a warning tool, then confirm signals with trend direction, support and resistance, moving averages or divergence. Used this way, the William index becomes less of a guessing tool and more of a disciplined timing filter.
