Trendline

Stock trading dictionary: meaning, example and how traders use it.

Last updated: October 17, 2026

Definition: A trendline is a straight line drawn on a price chart connecting two or more lows in an uptrend or two or more highs in a downtrend. It shows the trend's direction and slope and can act as dynamic support or resistance.

How a trendline works

A trendline turns the idea of a trend into something visible. In an uptrend, the line connects rising swing lows and sits below price, acting as moving support. In a downtrend, it connects falling swing highs and sits above price, acting as moving resistance. Two points are enough to draw a line, but a third touch is often considered confirmation that the line matters to market participants.

The steeper the line, the faster the trend, and the more likely it is to be broken. Gentle slopes tend to be more durable.

How to draw a trendline

  1. Choose a timeframe and identify clear swing lows (uptrend) or swing highs (downtrend).
  2. Connect at least two of those points with a straight line, extending it to the right.
  3. Avoid forcing the line through price bars; minor overshoots are normal, but frequent violations mean the line is not useful.
  4. Decide consistently whether to use wicks or bodies on candlestick charts or the extremes of a bar chart.

Some traders use a logarithmic price scale for long-term trendlines, since it reflects percentage moves more evenly.

Trendline example

Suppose a stock makes lows at $20 in February and $24 in April. A line through them rises about $2 per month, projecting to roughly $28 in June. In June the stock dips to $28.10 and rebounds, a third touch that confirms the line. In August, when the line projects near $32, the stock closes at $29 on heavy volume. The trendline has broken, a warning that the uptrend may be weakening or heading for a reversal.

Trendlines vs channels and moving averages

A channel adds a second line parallel to the trendline, drawn through the opposite swing points, creating a band that frames the trend. Traders may view moves toward the upper line of a rising channel as extended and moves toward the lower line as potential buying areas. Moving averages offer a more mechanical alternative, since they are calculated rather than drawn and adjust automatically to price. Many analysts use both: the trendline highlights the specific points the market has respected, while a moving average smooths out noise. Agreement between them strengthens a reading.

Limitations of trendlines

Trendlines are subjective: two traders can draw different lines on the same chart. A break does not always mean the trend has reversed; it may simply shift into a slower climb or a sideways range. Prices can also pierce a line briefly before resuming, so many traders wait for a close beyond the line or combine it with other tools, such as moving averages, before making decisions with charting.

Frequently asked questions

How many points do you need to draw a trendline?

Two points are needed to draw a line, but many traders consider a trendline more reliable once price has touched it a third time and respected it.

What does a trendline break mean?

A decisive close beyond a trendline suggests the trend is losing strength. It can signal a reversal, though sometimes the trend simply continues at a different angle.

Should you draw trendlines on wicks or candle bodies?

Both approaches are used. The key is consistency and choosing the method that best fits how the price has actually respected the line.

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For information only, not investment advice. See the disclaimer.