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Technical analysis

Williams Percent Range

By Jarosław Wasiński • Published: • Updated:
An oscillator locating Close in a selected High–Low range on a scale from −100 to zero. With matching windows it equals raw stochastic %K minus 100. Fourteen periods and −20/−80 levels are common conventions. Extreme readings guarantee no reversal and are not loss percentages or probabilities.
Example. With window High = 1.1100, Low = 1.1000 and Close = 1.1080, %R = −100 × (1.1100 − 1.1080)/(1.1100 − 1.1000) = −20. Raw stochastic on the same data is 80, so %R = raw %K − 100. The identity need not apply to smoothed %K.

What the value describes

Williams %R measures Close’s distance from the highest price relative to the entire range. Close at High gives zero; at Low, −100. It is a location scale rather than a percentage loss, return or probability of a future movement. The popular 14-period setting is a convention that should be stated explicitly.

Use a consistent window

High, Low and Close must belong to the same price series and matching window. An unfinished candle can alter the reading. A zero range requires a defined software handling rule. Smoothing or different windows can make a platform’s stochastic and %R readings inconsistent with the simple identity, despite similar-looking settings.

Extremes and trading rules

Levels of −20 and −80 define conventional interpretive regions, not certain reversals. In a trend, values can remain extreme. A rule may examine persistence, crossings or leaving a region. No application is universally best; evaluate the complete entry, exit and costs on suitable data rather than assume the scale provides an independent forecast.

Source of the definition

MetaTrader: Williams %R calculation. Documentation of the construction or concept is not a guarantee of strategy results.

FAQ

Does −20 mean a 20% loss?
No. It locates Close in the window range, not account performance.
Is %R simply negative stochastic?
No. With matching unsmoothed data, %R = raw %K − 100, not −%K.

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Jarosław Wasiński

Editor-in-chief, ForexMechanics.com • Macro & FX analyst

Independent analyst and practitioner with over 20 years of experience in financial markets. Actively involved in Forex since 2007, with a focus on fundamental analysis, OTC market structure, and disciplined capital risk management.

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