Skip to content

What is RSI Indicator? | Relative Strength Index Explained

What is RSI Indicator? | Relative Strength Index Explained
Diana Paluteder

The following guide will examine the relative strength index (RSI), what it is and what it measures, how to understand the indicator on charts and interpret those findings, as well as the pros and cons of using this technical analysis tool. 

Best Crypto Exchange for Intermediate Traders and Investors

  • Invest in 70+ cryptocurrencies and 3,000+ other assets including stocks and precious metals.

  • 0% commission on stocks - buy in bulk or just a fraction from as little as $10.

  • Copy top-performing traders in real time, automatically.

  • Regulated by financial authorities including FCA and FINRA.

2.8 Million Users
eToro is a multi-asset investment platform. The value of your investments may go up or down. Your capital is at risk. eToro USA LLC does not offer CFDs, only real Crypto assets available. Don’t invest unless you’re prepared to lose all the money you invest.

What is the RSI indicator?

The RSI is displayed as an oscillator, i.e., a line graph on a scale of zero to 100. It was developed by J. Welles Wilder Jr. and explained in detail in his 1978 book, “New Concepts in Technical Trading Systems.”

The momentum oscillator can demonstrate overbought and oversold conditions, as well as point to a general trend or securities that may be primed for a trend reversal or corrective pullbacks in price. Traders typically interpret the RSI line moving below the overbought line or above the oversold line as a signal to buy or sell


Beginners’ corner:


How does the RSI indicator work?

The RSI is usually based on a 14-day time frame, but this can be lowered to increase sensitivity or raised to decrease sensitivity. For example, 10-day RSI is more likely to reach overbought or oversold levels than a 20-day RSI. 

Generally, an RSI reading of 70 or above indicates overbought conditions. Conversely, a reading of 30 or below points to an oversold situation. However, these traditional levels can be altered to fit the particular security better. For instance, if the security is repeatedly reaching the overbought level of 70, you may want to alter this level to 80.

Knowing the asset’s primary trend is crucial for understanding RSI readings correctly. For example, as proposed by Constance Brown in “Technical Analysis for the Trading Professional,” an oversold reading in an uptrend is possibly much higher than 30. Similarly, an overbought reading during a downtrend is much lower than 70. 

Many investors create a horizontal trendline (a line drawn over the highs and under the lows to create a channel) between 30 and 70 when a strong trend is in place to identify the overall trend and extremes better.

However, modifying overbought or oversold RSI levels when the price of a security is in a long-term horizontal channel instead of a solid upward or downward trend is usually unnecessary.

The RSI is not as reliable in trending markets as in trading ranges. In fact, most traders accept that the signals given by the RSI in strong upward or downward trends often can be false.

Recommended video: Beginners guide to the RSI indicator

YouTube Trading 212

The RSI indicator formula

The RSI uses a two-part calculation. First, it is required to calculate the relative strength (RS), which equals the average gain divided by the average loss:

RS = Average Gain / Average Loss

Then, once there are 14 (the standard number of periods recommended by Wilder) periods of data available, the second calculation can be made. The formula is as follows:

RSI = 100 – (100 / (1+RS))

Example RSI calculation

For example, during a 14-day trading period, let’s assume that stock ABC has generated positive returns on nine days with an average gain of 2% and negative returns on five days with an average loss of 1%. Then, plugging those figures into the two formulas, we get:

RS = 0.02 / .01 = 2

RSI = 100 – 100 / (1 + 2) = 66.67

Note: Do not confuse RSI and relative strength (RS). The former refers to changes in the price momentum of one security. The latter compares the price performance of a security to the market as a whole or to a relevant benchmark.

How to use the RSI indicator?

Traders can use the RSI indicator to:

  • Predict the price behavior of an asset;
  • Validate trends and trend reversals;
  • Point to overbought and oversold securities;
  • Identify buy and sell signals;
  • Develop a trading strategy in conjunction with other technical analysis tools.

RSI indicator buy and sell signals

RSI buy and sell signals can be determined by:

  1. Identifying overbought and oversold conditions;
  2. RSI divergence indicator;
  3. Positive and negative RSI reversals;
  4. Swing rejections;
  5. Interpreting RSI ranges.

1. Identifying overbought and oversold conditions

Typically, an RSI less than 30 is considered a bullish sign, while RSI above 70 is regarded as a bearish sign. Additionally, when the RSI indicator crosses 70 on the RSI chart, it indicates that an asset is becoming overbought or overvalued, i.e., it may be primed for a trend reversal or corrective price pullback. Conversely, an RSI of 30 or below suggests an oversold or undervalued condition.

RSI indicator signals overbought or oversold conditions.
How RSI signals overbought or oversold conditions. Source: Museumxaser.weebly.com

Overbought describes a period with a significant and consistent upward movement in price over time without much pullback. It is a term used when an asset is believed to trade at a price beyond its intrinsic value, meaning it’s priced above where it should be according to technical and fundamental indicators. Overbought conditions may indicate a price correction or trend reversal and signal traders to exit (sell) a position.

On the other hand, oversold defines a period with a substantial and consistent downward move in price over time without much pullback. The term refers to a condition where a security has traded well below its typical value metrics and has the potential for a price bounce. Similarly, oversold conditions may indicate a price correction or trend reversal and signal traders to enter (buy) a position. 

For example, suppose a trader witnesses the RSI breaking above 70, indicating overbought conditions. In that case, they shouldn’t immediately sell their positions because they don’t know how far the price could rally. Instead, they should wait until the RSI falls back below 70 and then place their sell trade. This provides the trader with a better entry and a higher probability trade.

The same rules apply in oversold conditions. Traders should wait until the RSI crosses back above 30 before they place a buy trade.

2. RSI divergence indicator

Divergences occur when the price moves in the opposite direction of the RSI, i.e., a chart might indicate a change in momentum before a corresponding price change.

A bullish divergence occurs when:

  • The price chart displays prices falling to lower lows, signified by a downward-sloping line connecting the lows;
  • The RSI chart displays an oversold reading followed by lows moving higher, signified by an upward-sloping line connecting the lows.
Bullish divergence RSI indicator chart.
Bullish divergence RSI chart. Source: Thinkmarkets.com

Together, these two conditions indicate rising bullish momentum, and a break above oversold territory could be used to trigger a new long position.

A bearish divergence occurs when:

  • The price chart displays highs moving higher, signified by an upward-sloping line connecting the highs;
  • The RSI chart displays an overbought reading followed by highs moving lower, signified by a downward sloping line connecting the highs.
Bearish divergence RSI indicator chart.
Bearish divergence RSI chart. Source: Thinkmarkets.com

Together, these two conditions indicate rising bearish momentum.

3. Positive and negative RSI reversals

Another price-RSI relationship that traders look for is positive and negative RSI reversals. Positive and negative reversals are the opposite of bearish and bullish divergences.

For example, a positive RSI reversal may occur if the RSI reaches a low that is lower than its previous low, simultaneously with the asset’s price reaching a low that is higher than its previous low price. Such a formation is viewed as a bullish sign and, thus, a buy signal for traders.

Positive reversal on a chart. Source: School.stockcharts.com

Negative RSI reversal, on the other hand, may occur once the RSI reaches a high that is higher than its previous high at the same time that the asset’s price reaches a lower high. Such a formation is considered a bearish sign and, therefore, a sell signal for traders.

Negative reversal on a chart. Source: School.stockcharts.com

4. Swing rejections

Unlike RSI divergences and positive-negative reversals, swing rejections or failure swings are independent of price action, focusing solely on RSI for signals.

A bullish failure swing forms when:

  1. The RSI drops into oversold territory (below 30);
  2. The RSI bounces back above 30;
  3. The RSI establishes another dip without moving back into oversold territory;
  4. The RSI then breaks its prior high.

Using the RSI in this particular way is very similar to drawing trend lines on a price chart.

Bullish failure swing signal. Source: School.stockcharts.com 

The bearish failure swing forms when:

  1. The RSI climbs into overbought territory (above 70);
  2. The RSI drops back below 70;
  3. The RSI establishes another high without moving back into overbought territory;
  4. The RSI then breaks its prior low.

As with most trading strategies, this signal will be most reliable when it follows the long-term trend. In addition, bearish signals during downward trends are less likely to provoke false alarms.

Bearish failure swing signal. Source: School.stockcharts.com

5. Interpreting RSI indicator ranges

RSI readings may fall into a range during trends. For example, during an uptrend, the RSI is likely to stay above 30 and should frequently hit 70. On the other hand, during a downtrend, it is rare to see the RSI exceed 70; instead, the indicator frequently hits 30 or below.

These guidelines can help traders determine trend strength and spot potential reversals. For example, if the RSI can’t reach 70 on several consecutive price swings during an uptrend but then drops below 30, the trend has weakened and could be reversing lower. 

Conversely, if the downtrend cannot reach 30 or below and then rallies above 70, that downtrend has weakened and could be reversing to the upside. Remember, both trend lines and moving averages are helpful technical tools to include when using the RSI in this way.

Best Crypto Exchange for Intermediate Traders and Investors

  • Invest in 70+ cryptocurrencies and 3,000+ other assets including stocks and precious metals.

  • 0% commission on stocks - buy in bulk or just a fraction from as little as $10.

  • Copy top-performing traders in real time, automatically.

  • Regulated by financial authorities including FCA and FINRA.

2.8 Million Users
eToro is a multi-asset investment platform. The value of your investments may go up or down. Your capital is at risk. eToro USA LLC does not offer CFDs, only real Crypto assets available. Don’t invest unless you’re prepared to lose all the money you invest.

Pros and cons of RSI indicator

Like with most other technical indicators, the relative strength index, too, comes with its own set of unique benefits and limitations. Therefore, it’s crucial to understand where this particular momentum indicator triumphs and where it fails to get the most out of its use.

Pros

Pros

  • Applicable to any market and timeframe;
  • Helps to detect potential entry (buy) and exit (sell) points;
  • Gives an overview of general price movement, trends, and trend reversals;
  • Straightforward setup;
  • Relatively easy to evaluate and gain needed information;
  • Helpful as a stand-alone tool or in combination with other technical indicators.
Cons

Cons

  • Applicable to any market and timeframe;
  • Helps to detect potential entry (buy) and exit (sell) points;
  • Gives an overview of general price movement, trends, and trend reversals;
  • Straightforward setup;
  • Relatively easy to evaluate and gain needed information;
  • Helpful as a stand-alone tool or in combination with other technical indicators.

In conclusion 

To sum up, the RSI measures the speed of an asset’s price changes and is used in technical analysis as a momentum indicator. As a result, it can be a powerful tool for determining trend reversals. However, because the RSI works best in oscillating markets rather than trending markets, it cannot tell investors exactly when those reversals will take place and what those price changes will be. 

Additionally, the RSI is likely to generate false signals and should thus be used in conjunction with additional technical analysis tools rather than as a standalone source of trading signals.

Disclaimer: The content on this site should not be considered investment advice. Investing is speculative. When investing, your capital is at risk. 

FAQs about the RSI indicator

What is the RSI indicator?

The RSI indicator is a momentum indicator used in technical analysis that measures the speed of an asset’s price changes. It provides traders with signals about bullish and bearish price momentum and is typically plotted under the security’s price graph.

How does the RSI indicator provide buy and sell signals?

The RSI indicator buy and sell signals are typically determined by specific threshold levels. A security is considered overbought when the RSI reading is above 70 and oversold when it is below 30. Traders generally interpret the RSI line moving below the overbought line or above the oversold line as a signal to buy or sell. 

How can I interpret the RSI chart?

An RSI chart plots the Relative Strength Index values over time, ranging from 0 to 100. Traders look for potential overbought or oversold conditions, as well as bullish or bearish divergences between the RSI and the price chart. Overbought is typically above the 70 level, and oversold is below the 30 level on the RSI chart.

What are the RSI limitations?

Like most technical indicators, its signals are most reliable when they conform to the long-term trend. Unfortunately, accurate reversal signals are rare and can be challenging to separate from false alarms. Additionally, since the RSI is measuring momentum, it can remain in the overbought or oversold territory despite trend reversals already taking shape. Therefore, it is most trustworthy in an oscillating market when the price alternates between bullish and bearish periods rather than in trending markets. 

Is there an RSI indicator app for mobile trading?

Yes, many trading platforms and apps offer the RSI as a built-in tool.

Is the RSI indicator available on TradingView?

Yes, the RSI indicator TradingView offers is among the platform’s suite of tools. You can add it to any chart, customize its settings, and even combine it with other indicators and scripts for a comprehensive technical analysis.

How to use RSI indicator?

The RSI is a momentum oscillator that gauges the speed and change of price movements. Use it by monitoring levels above 70 (potentially overbought) and below 30 (potentially oversold) for trading cues. Look for divergences between RSI and price for potential reversals, and consider centerline crossovers (above or below 50) as bullish or bearish signals, respectively. The RSI’s effectiveness can be enhanced when combined with other technical tools and adjusting its standard 14-period setting based on your strategy. Always remember to incorporate it within a broader trading context for optimal results.

Is RSI a lagging indicator?

The RSI indicator is generally considered a leading indicator in technical analysis. It is designed to measure the speed and change of price movements, predicting future trends rather than just reporting past ones. However, like all indicators, it does have a component of lag because it relies on historical data to calculate its value. Despite its forward-looking nature, the RSI can sometimes provide late signals in rapidly changing market conditions. Therefore, while it is primarily used as a leading indicator to anticipate price movements, its effectiveness can be influenced by the speed and volatility of the market.

What is the difference between stochastic indicator vs RSI?

The Stochastic indicator and the RSI are both momentum oscillators in technical analysis, but they differ in sensitivity and calculation methods. The Stochastic indicator, more sensitive to immediate price movements, compares a security’s closing price to its price range over a specific period, often resulting in more frequent signals and a higher likelihood of indicating overbought or oversold conditions. The RSI, smoother and less prone to rapid fluctuations, measures the speed and change of price movements, potentially providing fewer but more reliable signals. While Stochastics are preferred in volatile, sideways markets due to their sensitivity, the RSI is often more effective in identifying and confirming longer-term trends.

What are the best RSI indicator settings?

The best settings for the RSI indicator will depend on your trading strategy and the market conditions. However, the most commonly used setting is a 14-period timeframe. This setting offers a balanced view of recent price movements, making it versatile for various trading styles and markets. Traders may adjust the period shorter for more sensitivity or longer for smoother data in different contexts. It’s also important to combine RSI with other indicators and analysis techniques for more reliable trading signals.

Best Crypto Exchange for Intermediate Traders and Investors

  • Invest in 70+ cryptocurrencies and 3,000+ other assets including stocks and precious metals.

  • 0% commission on stocks - buy in bulk or just a fraction from as little as $10.

  • Copy top-performing traders in real time, automatically.

  • Regulated by financial authorities including FCA and FINRA.

2.8 Million Users
eToro is a multi-asset investment platform. The value of your investments may go up or down. Your capital is at risk. eToro USA LLC does not offer CFDs, only real Crypto assets available. Don’t invest unless you’re prepared to lose all the money you invest.

Weekly Finance Digest

By subscribing you agree with Finbold T&C’s & Privacy Policy

Related guides

Contents