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 stock and forex traders. Combine Mass Index reversal signals with momentum tools from our indicator guide library for higher-probability entries.
Mass Index = Sum of [EMA(9) of (High − Low) / EMA(EMA(9)) of (High − Low)] over 25 periods. When the Mass Index rises above 27 and then falls back below 26.5, it produces a reversal bulge signal. The direction of the reversal depends on the preceding trend and is confirmed by an EMA crossover.
Donchian Channels plot the highest high and lowest low over a specified period, forming a simple but effective volatility envelope and breakout system that powered the legendary Turtle Trading strategy. They are widely used in <a href="/market/forex" class="text-primary hover:underline">forex</a> and <a href="/market/crypto" class="text-primary hover:underline">crypto</a> for trend-following breakout <a href="/strategies" class="text-primary hover:underline">strategies</a>. Compare Donchian Channels with <a href="/academy/indicators/bollinger-bands" class="text-primary hover:underline">Bollinger Bands</a> and <a href="/academy/indicators/keltner-channels" class="text-primary hover:underline">Keltner Channels</a> in our <a href="/academy/indicators" class="text-primary hover:underline">indicator guide library</a>.
Price Envelopes plot fixed percentage bands above and below a <a href="/academy/indicators/simple-moving-average" class="text-primary hover:underline">Simple Moving Average</a>, creating a straightforward volatility channel for identifying overextended price moves and potential reversal zones. They are among the simplest band indicators available and work well in ranging <a href="/market/forex" class="text-primary hover:underline">forex</a> and <a href="/market/stocks" class="text-primary hover:underline">stock</a> markets. Compare Price Envelopes with <a href="/academy/indicators/bollinger-bands" class="text-primary hover:underline">Bollinger Bands</a> in our <a href="/academy/indicators" class="text-primary hover:underline">indicator guide library</a> to decide which suits your style.
Keltner Channels plot an EMA with upper and lower bands based on <a href="/academy/indicators/atr" class="text-primary hover:underline">ATR</a>, producing smoother envelopes than <a href="/academy/indicators/bollinger-bands" class="text-primary hover:underline">Bollinger Bands</a> — and the two are frequently used together for the TTM Squeeze setup. This combination identifies low-volatility compression zones that precede explosive <a href="/guides/trade-breakouts" class="text-primary hover:underline">breakout</a> moves in any market. Apply Keltner Channels on <a href="/tools/platforms/tradingview" class="text-primary hover:underline">TradingView</a> and overlay Bollinger Bands to spot squeeze conditions with a single glance.
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 <a href="/market/stocks" class="text-primary hover:underline">stocks</a> and increasingly in <a href="/market/crypto" class="text-primary hover:underline">crypto</a> derivatives. Use our <a href="/tools/calculators/position-size-calculator" class="text-primary hover:underline">position size calculator</a> to incorporate HV into your risk management workflow.