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Support and resistance are price areas where earlier swings turned, and a trendline is a sloped version of the same idea. Draw them from confirmed swing points, write down what would invalidate them, and expect a broken line to change the pace of a trend before it changes the direction.
What support and resistance are
Support is a price area where declines have stopped before, and resistance is a price area where advances have stopped before. They are areas rather than exact prices, because swings rarely turn at the same cent twice. They matter because many participants watch the same prior highs and lows, and orders placed around those prices can slow a move when price returns to them.
A level becomes more relevant with each clear turn at it, with heavy volume at it and with time: a level that held for a year carries more history than one from last week. None of that makes it certain to hold again; it makes it a price worth writing down.
How to draw support and resistance levels
Draw horizontal levels at prices where the chart already turned. Use a daily chart long enough to show several swings, mark the swing highs and swing lows, and draw a level where two or more of them line up. Decide whether you anchor on wicks or on closes, and use the same choice everywhere.
- Swing highs and swing lows with at least two turns near the same price.
- Prior highs and lows, such as the highest high of the last 52 weeks.
- Round numbers such as $50 or $100, where orders can cluster.
- The previous close before a gap, which is the gap’s fill level.
- The top and the bottom of a base or a trading range.
Give each level a width. A zone of about half the average true range, or 1% of the price, around the line accepts the small overshoots that real swings produce. In the figure further down, swing highs at 47.00 and 46.95 define a resistance level at 47.00.
Horizontal support vs trendline support
Horizontal support is a fixed price; trendline support rises with time, so it marks where a pullback would stop if the trend kept its pace. Moving averages are a third, calculated kind of level that moves with price. Each answers a different question, and they say the most when they agree.
| Kind | Defined by | What it tracks | Main weakness | How to keep track of it |
|---|---|---|---|---|
| Horizontal | Two or more swing points near one price | A price where buyers stepped in before | Says nothing about the pace of the trend | Write the price down; compare it with hi20FromLowPct or hi52wFromLowPct |
| Trendline | Two swing lows, confirmed by a third touch | The pace of an uptrend | Depends on the points chosen and on the chart’s scale | Write the two anchors down and compute the line for later sessions |
| Moving average | A calculation over a fixed number of sessions | The average price of recent sessions | Lags at turns, and is a level only by convention | Overlay it in Stock Charts; read distSma50Pct or distSma200Pct |
securityType = "Stock" and sma50 > sma200 and distSma50Pct >= 0 and distSma50Pct <= 2Stocks whose 50-session average is above the 200-session average and whose close is between 0% and 2% above the 50-session average, near the average used as a moving level.
How to draw a trendline on a stock chart
An uptrend line connects two confirmed swing lows, the second higher than the first, and extends to the right; a downtrend line connects two swing highs, the second lower than the first. Two touches define a line, and a later third touch that holds confirms it. The line should not cut through the candles between its anchors; if it does, the anchors were chosen to fit rather than found.
Slope = (second anchor price − first anchor price) ÷ (second anchor session − first anchor session)
Line value at session t = first anchor price + slope × (t − first anchor session)anchor- a confirmed swing low for an uptrend line, or a swing high for a downtrend line; the two anchors must fall on different sessions
| Measure | Value |
|---|---|
| First anchor | Session 4, low $40.00 |
| Second anchor | Session 16, low $42.40 |
| Slope | $0.20 per session |
| Line value at session 28 | $44.80 |
| Third touch | Session 28, low $44.90, 0.22% above the line |
| First close below the line | Session 48, close $48.40, 0.82% below a line value of $48.80 |
Stock Charts in TradeClever has no drawing tools, so keep the two anchors in your notes and compute the line’s value for the sessions you review, as in the table. Over a long history, a straight line on a logarithmic price scale and one on a linear scale drift apart, so note which scale you used.
How to validate a stock trendline
A trendline earns trust when it was drawn before the touches that test it. The checks below separate a line that describes the trend from one fitted to it after the fact; in the figure, no session closes below the line between the first anchor and session 48.
- Both anchors are confirmed swing points, not arbitrary bars.
- No close falls below the line between the anchors.
- A third touch comes later and holds: price reaches the line, within a tolerance such as 1% or half the average true range, and closes above it.
- The slope is sustainable: a very steep line leaves no room for an ordinary pullback, so it breaks easily.
- The line spans enough sessions to matter for your horizon.
- You wrote the line down before the third touch, together with the close that would invalidate it.
Counter-example: a line through the session-4 low and whichever later lows happen to line up, drawn after you have already seen the third touch, always looks validated. Only touches that came after the line was drawn count as validation.
When resistance turns into support, and support into resistance
After a level breaks, it often changes role. Former resistance that price has closed above can act as support on the next decline, and former support that price has closed below can act as resistance on the next rally. The usual explanation is that participants who missed the breakout, or who held through the breakdown, act near the old level when price returns to it.
In the figure, resistance at 47.00 holds at sessions 21 and 25. Session 32 closes at 47.80, above the level, and the retest in session 37 reaches 47.10 without closing below 47.00, so the former resistance has acted as support once. A broken support that caps the next rally follows the same logic in the opposite direction.
Counter-example: a level that breaks and then sees price close back on the other side within a session or two has not changed role; that is a failed breakout or breakdown. A role reversal needs the break to hold on a closing basis and the retest to fail to undo it.
Trendline break vs trend reversal
A close below an uptrend line says that the trend lost its former pace. It does not by itself say that the trend reversed. A reversal needs a change in structure, a lower high and a lower low, or a close below the last higher low; after a trendline break, price can reverse, move sideways or continue along a flatter line.
In the figure, session 48 closes 0.82% below the trendline. The lows that follow, 47.60 and 47.70, stay above the last higher low of 47.10, while the next high, 49.40, is below the prior high of 50.00. The structure turned into a narrowing range rather than a downtrend.
| Outcome | What confirms it |
|---|---|
| Reversal | A lower high, then a close below the last higher low |
| Sideways range | Highs and lows that stay between two levels |
| Flatter uptrend | A new higher low and a higher high along a less steep line |
Invalidation, and how to keep track of levels
A level without an invalidation rule never fails, which makes it useless for research. For each level, write down the price, the zone width, how it was drawn and the close that would end it, such as two closes beyond the zone. Review the list as new sessions arrive and retire levels that no longer matter.
Because TradeClever has no drawing tools, the record lives in your notes. Levels that follow from the data can still be checked with CleverScan fields: hi20FromHighPct, hi50FromHighPct and hi52wFromHighPct measure how far the close sits below the highest high of the last 20, 50 and 252 sessions, and the matching FromLowPct fields measure the distance above the lowest low.
securityType = "Stock" and hi52wFromHighPct >= -3Stocks closing within 3% of the highest high of the last 252 sessions, a prior-high resistance area to review on the chart.
securityType = "Stock" and close > sma200 and hi20FromLowPct <= 2Stocks above their 200-session average that closed within 2% of their 20-session low, near a short-term support area.
- Open a 1Y daily chart and mark the confirmed swing highs and swing lows.
- Draw horizontal levels where two or more swings line up, and give each one a zone.
- Draw a trendline through two swing lows or two swing highs, and compute its value for later sessions.
- Write the invalidation for each level and line before price returns to it.
- When a level breaks, watch the retest for a role reversal or a failed break.
- Judge a trendline break by the structure that follows, not by the break alone.
Continue with
Sources
- Robert D. Edwards and John Magee, Technical Analysis of Stock Trends (first published 1948)
Read our data and methodology notes for calculation context. This guide explains research tools and observations. It does not recommend a trade or investment.