Relative Strength Index – RSI

What is Relative Strength Index ?

Short note on relative strength index: Relative strength index is technical indicator which compares current and historical gains and losses in order to define if the asset’s value is over priced or under priced. Formula for calculating RSI is:

RSI = 100 – 100/(1 + RS*)
RS = Average of x days’ up closes / Average of x days’ down closes
Relative strength index math:

Main role of this indicator is to remove noise in price movement representation. High relative strength index success rate we can see in application very often.
Example of GBPUSD chart – RSI indicator is red:

what does the relative strength index tell you ? Interval in which RSI ranges is from 0 to 100 and it shows if asset is overvalued or undervalued (relative strength index law). In fact, as the RSI closes to level 70, the asset can be considered overvalued and has a big chance to be overbought. On the other hand, when RSI reaches level 30 the asset is deemed to be oversold. The best way to use this index is as a additional information to other stock-picking tools because using only RSI trader can create false buy and sell signals which can mislead observer.

History of relative strength index

The relative strength index was developed by J. Welles Wilder and published in a 1978 book, New Concepts in Technical Trading Systems, and in Commodities magazine (now Futures magazine) in the June 1978 issue.It has become one of the most popular oscillator indices.The RSI compares bullish and bearish price momentum plotted against the graph of an asset’s price. Wilder developed Average True Range, the Relative Strength Index (RSI), Average Directional Index, and the Parabolic SAR.

Relative strength index algorithm – How to calculate relative strength index in excel ?

I always get information from MetaTrader. So how to calculate relative strength index using excel manually ? The most simple method we can see in nice post Calculation of RSI using EXCEL.
Idea is to define close price in some time period and than start relative strength index calculation excel :

“Column E” has all closing prices.
“Column F” calculates change in price by subtracting current row from previous row.
If “Column F” value is greater than zero, value will be copied to Column G. If value is less than zero, value will be copied to “Column H”.
“Column I” calculates the average Gain over the specified period, example 14.
“Column J” calculates the average Losses over the specified period, example 14.
“Column K” calculates the value of Relative Strength (RS).
“Column L” calculates the value of Relative Strength Index(RSI).
Please visit website and download relative strength index in excel tool: Download relative strength index formula excel

You can see in this nice video relative strength index example calculation:

How we can trade using this RSI indicator – advantages of using relative strength index ?

How does relative strength index work ? We can use RSI to determine overbought and oversold moment in trading. Below 30 is oversold and above 70 is overbought.There are some rules for traders :
– Market can be oversold or overbought very long time. It is not smart to trade sell orders above 70 and buy orders below 30 without deep analysis.
– Do not buy in oversold market or sell in overbought market without some conformation in your direction (for example some big move, strong bullish or bearish candle etc.)
– The best strategy is – buy or sell after pullback and respect main trend. For example if trend is bullish on daily or H4 chart, price is above 50 RSI in strong bullish direction you can buy if price goes in oversold area on 5 minute or 30 minutes chart. See images below :

On daily chart we see bearish trend. Next 7 days price will fall 300 pips down :

2) We can use RSI indicator to find divergence and predict change of the trend.On image below we can see relative strength index bullish divergence (relative strength index when to buy) :

On this image below we have relative strength index bearish divergence (relative strength index weakness) example:

Using RSI trend lines we can avoid very often false breakout in trading or Market Has Hit an Extreme.How important are levels 30 and 70 (relative strength index bloomberg example), we can see in nice highest rsi table. In this article we can see opinion “Many technical traders view anything above 70 as a sign that the dollar is overbought and due for a correction.”

3) My favorite way to use RSI – draw trend lines on RSI chart and use for trading !
Traders can draw trend lines below and above RSI line. If price breaks trendline than trend will change. See example :

This example shows bullish trend on 30 min chart.I can make buy orders above trendline but if price breaks RSI trendline than trend is changed.Of course on 30 minute chart we can see 25% from ATR bearish trend in price breaks this line (around 20 pips).If price breaks daily trendline RSI that can give few hunderds pips profit.

Questions and answers from email messages:

1) How to find relative strength index indicator in Metatrader ?
RSI is major indicator. It is in indicator section in group oscillators.

2. What is a good relative strength index number
Each number in RSI is “good”. It is just strength index. For example is price is above 70 or below 30 it can be excellent trend which can give more profit in future. Price around 50 can be in range market, but it can be strong trend decline or rise if we have strong divergence in that moment.

3. Should I set RSI settings on different way.Is it better rsi 8 or 14; rsi 7 vs rsi 14 ?
My advice is to use default settings. All major world traders use (mostly) the same settings so they will make decision based on default parameters.Summary, default settings is relative strength index best settings.

4. What are relative strength index disadvantages and what are advantages of using relative strength index ?
The biggest advantage is simplicity, easy reading as we see in chapter how relative strength index works. One of the biggest disadvantage is that rsi is very fast indicator and sometimes we need to wait for higher time frame price close conformation.