What Is a Trend Line in Trading?

What Is a Trend Line on a Stock Chart?

A trend line joins two or more turning points and extends their path forward. Imagine a stock recovering from $80, then later from $85. Joining those lows produces an upward-sloping line. These prices are illustrative.

A low where price turns upward is called a swing low. A high where it turns downward is a swing high. Lines under lows describe support; lines across highs describe resistance. The support and resistance guide explains those roles.

The line also changes with time. In our example, extending it tells you where that path reaches on a later date. You can compare the next decline with that location, then observe whether price recovers or crosses it.

Choose the Points and Extend the Line

The original points are called anchors. Two anchors determine a straight line; later approaches show how subsequent prices relate to it. If you move an anchor after a later decline, you are evaluating a different line.

• Choose a timeframe and chart scale before drawing.
• Connect distinct lows for a support line or distinct highs for a resistance line.
• Use the same price convention throughout, such as candle lows or closing prices.
• Extend the line without moving the original points to accommodate later prices.

What Counts as a Trend Line Touch?

A touch is an approach close enough to count under the rule being used. Prices seldom land exactly on a drawn line, so a repeatable method needs a consistent way to judge nearby prices.

Several adjacent candles near the line can belong to one prolonged visit. Separate visits, with price moving away between them, describe different events. A larger touch count alone does not establish a higher chance of recovery.

Trend Lines Across Daily, Weekly and Monthly Charts

Each daily candle summarizes one trading day; weekly and monthly candles combine longer periods. A line drawn from monthly turning points can describe years of movement, while a daily line may describe a recent pullback.

Choose the interval that matches the question. TradingPal’s support and resistance setup records use weekly and monthly charts. Compare a line with prices from its own series so its turning points and later tests remain consistent.

Where the Drawing Becomes Subjective

• Changing the anchors after seeing a later recovery selects a line with the outcome already known.
• Switching between candle extremes and closes can make an otherwise poor fit appear convincing.
• Changing the price scale changes how a straight line relates to the chart.
• Leaving the entry and exit unspecified makes it impossible to measure a trading result from the drawing.

Do Trend Lines Work? What Our Historical Study Found

Read the full research report for the recorded comparison, methods and limitations.

In our broad monthly and weekly study, raw trend lines by themselves did not produce a dependable bounce advantage over comparison locations. That negative result matters: a line can organize a chart without forecasting the next move.

That is why TradingPal publishes odds for a complete, repeatable setup—not for the mere presence of a line. The evidence panel below includes the qualification, entry, risk control, and exit. You can see how that evidence is separated and validated in how TradingPal backtests trendlines.

Use the Line to Ask a Specific Question

For the stock that recovered from $80 and $85, you now have a way to describe the path of those recoveries. To study a trade near its extension, specify how close price must come, when you would enter and how you would exit.

The trendline strategy guide develops those decisions. The historical discussion on this page explains why a line’s appearance and the results of a complete trading rule must be evaluated separately.

The sample, instrument scope and dates belong to this exact setup book. Extreme drawdowns remain visible rather than being hidden.

Backtest window: 2021-12-06 to 2026-07-13. Data snapshot: 7/23/2026. Historical results can differ from live fills and do not predict future performance.