What Is a Technical Indicator?
A technical indicator is a calculation derived from historical trading data, such as price, trading volume, or open interest. Investors who practice technical analysis use indicators to turn raw market data into charts and signals that are easier to interpret. Indicators are typically plotted on a price chart, either overlaid on the price itself or shown in a separate panel below it.
How Technical Indicators Work
Most indicators fall into a few broad groups. Trend indicators, such as moving averages, smooth out price data to show the direction the market has been moving. Momentum indicators, such as the relative strength index (RSI), measure how quickly prices are changing. Volatility indicators, such as Bollinger Bands, show how widely prices are spreading around an average. Volume indicators examine how much trading activity accompanies price moves.
A simple moving average, for example, is calculated as:
Simple Moving Average = (Sum of closing prices over N periods) / N
If a stock closes at 10, 11, 12, 13, and 14 over five days, its five-day simple moving average is 12. Traders often watch for the price crossing above or below this line as a possible sign of a change in trend.
Advantages and Limitations
Technical indicators offer a consistent, rule-based way to organize price data, and they can be applied to any market that has a price history. They also make it easier to compare securities on the same basis.
Their limitations are significant, however. Indicators are calculated from past data, so they lag behind current prices and cannot predict the future with certainty. Many indicators produce false signals, especially in choppy or sideways markets. Different traders may also choose different settings, such as a 14-day versus a 20-day period, which can produce different results from the same data.
Why It Matters to Investors
Understanding technical indicators helps investors read the charts and commentary that other market participants use. Many investors combine indicators with fundamental research, such as a company's earnings and balance sheet strength, rather than relying on any single signal. Indicators are best understood as tools for organizing information, not as guarantees of future results.
Updated October 17, 2026. For general education only; not financial, tax or legal advice.