Historical Volatility measures the annualised standard deviation of past log price returns, giving traders a statistical benchmark for how volatile an asset has been. It is essential for options pricing and risk management in stocks and increasingly in crypto derivatives. Use our position size calculator to incorporate HV into your risk management workflow.
HV = Standard Deviation of [ln(Close today / Close yesterday)] over N periods × √252 (for daily data annualisation). Common periods are 10, 20, and 30 days. Higher HV means the asset's price has been swinging more dramatically; lower HV means calmer price action.
The Mass Index identifies potential trend reversals by measuring the narrowing and widening of the range between high and low prices, generating a "reversal bulge" signal when the range first expands then contracts. It is a unique contrarian tool for <a href="/market/stocks" class="text-primary hover:underline">stock</a> and <a href="/market/forex" class="text-primary hover:underline">forex</a> traders. Combine Mass Index reversal signals with momentum tools from our <a href="/academy/indicators" class="text-primary hover:underline">indicator guide library</a> for higher-probability entries.
Bollinger Bands plot a moving average with upper and lower bands set at 2 standard deviations, expanding during high volatility and contracting during low volatility to create actionable squeeze and breakout signals. The Bollinger Squeeze is especially powerful when combined with <a href="/academy/indicators/keltner-channels" class="text-primary hover:underline">Keltner Channels</a> in the TTM Squeeze setup, a favourite of professional traders. Pair Bollinger Bands with the <a href="/academy/indicators/rsi" class="text-primary hover:underline">RSI</a> to filter false signals and confirm <a href="/guides/trade-breakouts" class="text-primary hover:underline">breakout entries</a>. Set them up on <a href="/tools/platforms/tradingview" class="text-primary hover:underline">TradingView</a> for real-time alerts and multi-timeframe analysis.
Standard Deviation measures the dispersion of closing prices from their mean over a given period, providing the mathematical foundation for <a href="/academy/indicators/bollinger-bands" class="text-primary hover:underline">Bollinger Bands</a> and many other volatility tools. Rising standard deviation signals increasing volatility across <a href="/market/stocks" class="text-primary hover:underline">stocks</a>, <a href="/market/crypto" class="text-primary hover:underline">crypto</a>, and <a href="/market/forex" class="text-primary hover:underline">forex</a>. Review our <a href="/academy/indicators" class="text-primary hover:underline">indicator guide library</a> to see how standard deviation powers multiple volatility-based trading tools.
ATR measures market volatility by calculating the average range of price bars over a specified period — it is essential for position sizing, stop-loss placement, and identifying volatility shifts. Use our <a href="/tools/calculators/position-size-calculator" class="text-primary hover:underline">position size calculator</a> to convert ATR readings into proper trade sizing instantly. Read the <a href="/guides/use-stop-loss-orders" class="text-primary hover:underline">stop-loss guide</a> and the <a href="/guides/calculate-position-size" class="text-primary hover:underline">position sizing guide</a> to master ATR-based risk management across every market. ATR adapts to any asset — apply it in <a href="/market/crypto" class="text-primary hover:underline">crypto</a>, <a href="/market/stocks" class="text-primary hover:underline">stocks</a>, and <a href="/market/forex" class="text-primary hover:underline">forex</a> for volatility-adjusted trading.