The trading volume may be considered the quintessential indicator. It shows the number of individual units traded for an asset in a given time. It basically shows how much of that asset changed hands during the measured time.
Some consider the trading volume to be the most important technical indicator out there. “Volume precedes price” is a famous saying in the trading world. It suggests that large trading volume can be a leading indicator before a big price move (regardless of the direction).
By using volume in trading, traders can measure the strength of the underlying trend. If high volatility is accompanied by high trading volume, that may be considered a validation of the move. This makes sense because high trading activity should equal a significant volume since many traders and investors are active at that particular price level. However, if volatility isn’t accompanied by high volume, the underlying trend may be considered weak.
Price levels with historically high volume may also give a good potential entry or exit point for traders. Since history tends to repeat itself, these levels may be where increased trading activity is more likely to happen. Ideally, support and resistance levels should also be accompanied by an uptick in volume, confirming the strength of the level.