What is the Stochastic Oscillator Indicator?
The Stochastic Oscillator is a momentum oscillator that measures where the current close sits relative to the high–low range over a recent lookback period, plotted on a 0–100 scale in a separate panel under price. It uses two lines, %K (the faster line) and %D (a smoothed signal line), with readings above 80 treated as overbought and readings below 20 treated as oversold. Traders use it to gauge whether closes are clustering near the top or bottom of the recent range, which reflects short-term momentum.
How is the Stochastic Oscillator Indicator Calculated?
The Stochastic Oscillator is calculated by converting the close’s position inside the lookback range into a percentage and then smoothing it into a signal line. The core formulas are:
- %K = [(Close − Lowest Low) / (Highest High − Lowest Low)] × 100
- %D = SMA(%K, 3)
“Highest High” and “Lowest Low” come from the last 14 periods by default (the classic 14,3 setting), and %D uses a 3-period simple moving average of %K to reduce noise.
How to Use the Stochastic Oscillator Indicator in Trading?
To use the Stochastic Oscillator in trading, treat it as a timing tool for pullbacks and range turns by focusing on overbought/oversold zones, %K/%D crossovers, and divergence versus price. Common ways traders apply it include:
- Overbought/oversold context: a reading above 80 flags strong closes near the top of the range; a reading below 20 flags strong closes near the bottom, which helps you look for exhaustion at resistance/support.
- %K/%D crossover trigger: go long when %K crosses above %D after the oscillator has been below 20; go short when %K crosses below %D after it has been above 80.
- Divergence for reversal pressure: bullish divergence forms when price makes a lower low while the oscillator makes a higher low; bearish divergence forms when price makes a higher high while the oscillator makes a lower high.
- Stops and invalidation: place the stop beyond the swing that proves the setup wrong (below the recent swing low for longs, above the recent swing high for shorts), not at an oscillator level.