Free Hurst Exponent Calculator

What is the Hurst Exponent?

The Hurst exponent (H) is a statistical measure that describes the long-term memory of a time series. Named after hydrologist Harold Edwin Hurst, who developed it while studying Nile river flooding patterns, the Hurst exponent has become essential for traders seeking to understand market regimes.

Unlike momentum indicators that simply measure recent price changes, the Hurst exponent reveals a deeper structural property: whether the market exhibits persistence (trending behavior) or anti-persistence (mean-reverting behavior).

How to Interpret Hurst Exponent Values

• H > 0.5 (Persistent/Trending): Price movements tend to continue in the same direction. Trends are likely to persist. Momentum strategies work better.
• H = 0.5 (Random Walk): No discernible pattern. Price changes are independent of past changes. Neither trend-following nor mean-reversion has an edge.
• H < 0.5 (Anti-Persistent/Mean-Reverting): Price movements tend to reverse. What goes up is likely to come back down. Mean-reversion strategies work better.

Why Use the Hurst Exponent for Trading?

The Hurst exponent answers a question that most indicators cannot: What type of market am I in?

Consider RSI (Relative Strength Index). When RSI shows "overbought," should you sell? It depends entirely on the market regime. In a strongly trending market (H > 0.6), overbought conditions often lead to more buying, not selling. In a mean-reverting market (H < 0.4), overbought signals are more reliable.

The Hurst exponent tells you which regime you are in, helping you choose the right strategy.

How is the Hurst Exponent Calculated?

This calculator uses Rescaled Range (R/S) Analysis, the classical method developed by Hurst:

1. Divide the time series into sub-periods of varying lengths
2. For each sub-period, calculate the range of cumulative deviations from the mean
3. Divide this range by the standard deviation (rescaling)
4. Plot log(R/S) against log(period length)
5. The slope of this line is the Hurst exponent

Tips for Accurate Results

• Use enough data: 100+ data points provide more reliable estimates
• Use consistent timeframes: Daily closes, hourly closes, etc. — do not mix
• Recalculate periodically: Market regimes change; Hurst values are not permanent
• Combine with other analysis: Hurst tells you the regime; use other tools for timing

Learn More About the Hurst Exponent

For a deeper understanding of how the Hurst exponent works and how to apply it in your trading, read our comprehensive guide:

The Hurst Exponent: Trend vs Range Detection →

See how the Hurst exponent compares to traditional indicators:

Hurst Exponent vs RSI: Which Regime Indicator Wins? →