Volatility Ratio

What Is the Volatility Ratio?

The volatility ratio is a technical measure used to identify price patterns and breakouts. In technical analysis, it uses true range to gain an understanding of how a security’s price is moving on the current day in comparison to its past volatility.

There are several different versions of volatility ratios, the most common being adaptations of average true range (ATR).

Key Takeaways

  • The volatility ratio measures relative changes in an asset's price movements in order to identify trading opportunities.
  • Technical traders employ true range, or the difference between the high and low prices on any given day, to reveal how volatile a stock is.
  • The most common version of a volatility ratio takes the proportion of an asset's day true range to its average true range.

Understanding Volatility Ratios

The volatility ratio is a measure that helps investors follow the volatility of a stock’s price. It is one of a few technical indicators focused on volatility. In general, the standard deviation is typically one of the most common measures used for following volatility. Standard deviation forms the basis for several technical channels including Bollinger Bands.

Comprehensive envelope channels of many different varieties are used by technical analysts to identify price ranges and volatility patterns that help lead to trading signals. Historical volatility is also another common trendline that can be used to follow volatility.

The volatility ratio was developed to contribute to the analysis of price volatility. Across the industry, volatility and volatility ratio calculations may vary. For technical analysis, Jack Schwager is known for introducing the concept of a volatility ratio in his book Technical Analysis.

Calculating the Volatility Ratio

Schwager’s methodology for calculating the volatility ratio builds on the concept of true range, which was developed and introduced by Welles Wilder but has several iterations. Schwager calculates the volatility ratio from the following:

VR = TTR ATR where: VR = Volatility Ratio TTR = Today’s True Range Today’s True Range = Max Min Max = Today’s High, Yesterday’s Close Min = Today’s Low, Yesterday’s Close ATR = Average True Range of the Past N-Day Period \begin{aligned} &\text{VR} = \frac { \text{TTR} }{ \text{ATR} } \\ &\textbf{where:} \\ &\text{VR} = \text{Volatility Ratio} \\ &\text{TTR} = \text{Today's True Range} \\ &\text{Today's True Range} = \text{Max} - \text{Min} \\ &\text{Max} = \text{Today's High, Yesterday's Close} \\ &\text{Min} = \text{Today's Low, Yesterday's Close} \\ &\text{ATR} = \text{Average True Range of the Past N-Day Period} \\ \end{aligned} VR=ATRTTRwhere:VR=Volatility RatioTTR=Today’s True RangeToday’s True Range=MaxMinMax=Today’s High, Yesterday’s CloseMin=Today’s Low, Yesterday’s CloseATR=Average True Range of the Past N-Day Period

Other iterations of the volatility ratio may include the following:

VR = TTR ATR where: | TTR | = Absolute Value of Max Absolute Value of Max = TH TL , TH YC , YC TL TH = Today’s High TL = Today’s Low YC = Yesterday’s Close \begin{aligned} &\text{VR} = \frac { \mid \text{TTR} \mid }{ \text{ATR} } \\ &\textbf{where:} \\ &\text{| TTR |} = \text{Absolute Value of Max} \\ &\text{Absolute Value of Max} = \text{TH} - \text{TL}, \text{TH} - \text{YC}, \text{YC} - \text{TL} \\ &\text{TH} = \text{Today's High} \\ &\text{TL} = \text{Today's Low} \\ &\text{YC} = \text{Yesterday's Close} \\ \end{aligned} VR=ATRTTRwhere:| TTR |=Absolute Value of MaxAbsolute Value of Max=THTL,THYC,YCTLTH=Today’s HighTL=Today’s LowYC=Yesterday’s Close
VR = TTR EMA where: EMA = Exponential Moving Average of the True Range of the Past N-Day Period \begin{aligned} &\text{VR} = \frac { \mid \text{TTR} \mid }{ \text{EMA} } \\ &\textbf{where:} \\ &\text{EMA} = \text{Exponential Moving Average of the True Range} \\ &\text{of the Past N-Day Period} \\ \end{aligned} VR=EMATTRwhere:EMA=Exponential Moving Average of the True Rangeof the Past N-Day Period

Volatility Ratio Signals

Investors and traders will have their own mechanisms for following and detecting patterns from the volatility ratio. This ratio is typically plotted as a single line on a technical chart either as an overlay or in its own display window.

A higher volatility ratio will signal substantial price volatility in the current trading day. In general, volatility can be a signal of disturbances or developments affecting the security’s price. Therefore, high volatility may lead to a new trend for the security’s price in either a positive or negative direction. Traders follow volatility and the volatility ratio in conjunction with other trading patterns to help confirm a trading signal for investment.

Investopedia does not provide tax, investment, or financial services and advice. The information is presented without consideration of the investment objectives, risk tolerance, or financial circumstances of any specific investor and might not be suitable for all investors. Investing involves risk, including the possible loss of principal.

Article Sources
Investopedia requires writers to use primary sources to support their work. These include white papers, government data, original reporting, and interviews with industry experts. We also reference original research from other reputable publishers where appropriate. You can learn more about the standards we follow in producing accurate, unbiased content in our editorial policy.
  1. Jack D. Schwager. "Technical Analysis," Page 632. John Wiley & Sons, Inc, 1996.