The best timeframe for the Stochastic Oscillator is the 1-hour chart with the standard 14-period setting, which backtesting shows produces the most reliable signals across most markets.
Testing from the liberated Stock Trader indicates that the best setting for Stochastics is 14 on an OHLC 1-hour chart, which yields a 43% win rate, while Stochastics-14 on all other timeframes underperformed average stock market returns.
Your ideal timeframe still depends on style: day traders prefer 5-minute or 15-minute charts for quick decisions, while swing traders favor daily charts to capture longer trends.
The strongest approach is layered: use the daily or 4-hour chart to identify the overall trend, the 1-hour to confirm trade direction, and the 15-minute chart to fine-tune entries.
Backtesting shows this approach can boost signal accuracy by 15-20%.