Stock market traders who use short-term strategies like day trading or buying and selling stock options rely heavily on the information contained in stock charts. To the novice, these charts can be intimidating, packed as they are with graphs, abbreviations and numbers from top to bottom. Actually, a stock chart isn't very complicated---it just looks that way. It's easy to learn how to read volume on stock charts as well as the other data presented. The real challenge is to know how to relate volume on stock charts to the other items to get information you can use to predict a stock's behavior.
Start with the information that appears across the top of the chart. The first items are the date the chart refers to along with the name and ticker symbol of the stock. Next, you'll find price information, giving the day's high, low and closing figures for the stock. Along with this, you'll read the volume on a stock chart. This is the daily volume of shares traded. There's usually one more piece of information listed, called the moving average. This is indicated by the letters MA followed by a number in parentheses and a price. This is the average price the stock traded over the number of days indicated by the number in parentheses.
Look at the rest of the stock chart. You will see two graphs, one in the middle of the page and a bar graph across the bottom. The one in the middle will consist of a line graph with the line bracketed by a bar (also called a candlestick) for each day the chart covers. This is really three graphs in one. Those bars don't refer to the day's volume but to the price range for the stock each day. The top of each bar or candlestick shows the daily high, and the bottom shows the low. The line graph itself shows the closing price.
Examine the bar graph at the very bottom of the page. This graph records the volume of shares traded for each day the chart covers. The height of the bar indicates the number of shares traded. Use the scale (usually located on the far left) to determine how many shares the height of each bar represents.
Learn how to read volume on stock charts in the context of the other information you see on the chart. Changes in the volume of trading can be very informative. For example, if you see an increasing number of shares being traded and the stock is in an upward trend, it indicates that investors are bidding up the stock price. An experienced trader will watch for a drop in that volume that may signal the upward climb in prices is reaching its peak.
Based in Atlanta, Georgia, W D Adkins has been writing professionally since 2008. He writes about business, personal finance and careers. Adkins holds master's degrees in history and sociology from Georgia State University. He became a member of the Society of Professional Journalists in 2009.