# Compression and Expansion

> Markets alternate between quiet compression and explosive expansion. Learn how to spot compression with ranges, ATR and Bollinger Bands, and trade the breakout.

Source: https://learn.tradelabsai.com/price-action/compression-and-expansion/  
Track: Price Action · Level: Beginner · Updated: 2026-10-03  
Publisher: TradeLabs AI (https://tradelabsai.com). Education, not financial advice.  
Cite as: TradeLabs Learn, "Compression and Expansion", https://learn.tradelabsai.com/price-action/compression-and-expansion/

Volatility moves in cycles. Periods of small, tightening ranges, called **compression**, are often followed by periods of large, fast moves, called **expansion**. Then the cycle repeats. Traders sometimes summarise it as "quiet markets get loud and loud markets get quiet." Recognising compression helps you prepare for a breakout before it happens, rather than chasing it afterwards.

## What compression looks like

- Candle ranges shrink day after day.
- Highs get lower and lows get higher, forming a triangle or wedge. See [Symmetrical Triangle](https://learn.tradelabsai.com/chart-patterns/symmetrical-triangle/).
- Bollinger Bands narrow, sometimes called a squeeze. See [Bollinger Bands](https://learn.tradelabsai.com/indicators/bollinger-bands/).
- Average true range falls to a low reading relative to recent history. See [ATR (Average True Range)](https://learn.tradelabsai.com/indicators/atr/).
- Volume often declines as participants wait.

## Why compression leads to expansion

During compression, buyers and sellers are balanced and orders build up just above and below the narrowing range: breakout entries, stop losses from both sides and waiting buyers and sellers. When price finally breaks out, those orders trigger together, producing a burst of activity. Volatility itself also tends to revert to its average, so extremely low volatility rarely lasts.

**Example: A volatility squeeze**
A stock's daily range shrinks from about $2.50 to $0.80 over three weeks. Its 20 day Bollinger Band width falls to its lowest level in six months, and volume drops by a third. Then a session opens above the compression range on heavy volume and moves $4 in two days. Traders who had marked the compression and placed orders just outside it caught the expansion; others noticed only after the big candles appeared.

## Measuring compression

| Tool | Compression signal |
|---|---|
| Range of recent candles | Several consecutive narrow range candles, such as the narrowest range of the last 7 days (NR7) |
| ATR | ATR at a multi month low |
| Bollinger Band width | Width at a multi month low |
| Bollinger inside Keltner Channels | Bands contract inside the channels, the classic "squeeze" setup. See [Keltner Channels](https://learn.tradelabsai.com/indicators/keltner-channels/) |
| Inside bars | A candle completely within the previous candle's range |

## Trading expansion

1. **Mark the compression range:** the high and low of the tight area.
2. **Plan both directions,** unless the trend gives a bias. Compression in an uptrend more often resolves upward, but not always.
3. **Enter on the break:** a stop order just outside the range, or wait for a candle close beyond it.
4. **Stop inside or on the other side of the range.** Tight compression allows tight stops.
5. **Target using volatility:** expansions often travel several times the compressed range.

See [Breakouts](https://learn.tradelabsai.com/price-action/breakouts/) for entry details.

## Traps to watch for

- **False breaks:** compression often ends with a fake move in one direction before the real move in the other. See [Failed Breakouts and False Breaks](https://learn.tradelabsai.com/price-action/failed-breakouts/).
- **News timing:** compression ahead of a scheduled event often resolves at the event, with gaps that skip stop orders.
- **Low volatility can persist:** some markets stay quiet longer than expected, producing many small losses on early breakout attempts.

## Expansion into exhaustion

The cycle continues after the breakout. Expansion phases end with very large candles, high volume and sometimes climactic reversals, after which a new compression begins. Recognising late, overextended expansion helps you avoid buying at the end of a move. See [Impulse and Correction](https://learn.tradelabsai.com/price-action/impulse-and-correction/).

## Common mistakes

- **Waiting for expansion to start before noticing compression,** then chasing.
- **Expecting a direction** without evidence; plan for both.
- **Using wide stops** after a tight compression; the setup's value is the tight risk.

## Frequently asked questions

### What is compression in trading?

A period of shrinking price ranges and falling volatility, often forming a tightening pattern before a breakout.

### What is a Bollinger Band squeeze?

When Bollinger Bands narrow sharply, signalling low volatility that often precedes a large move.

### Which direction will price break after compression?

There is no guaranteed direction. The prior trend and higher timeframe structure offer clues, but traders often prepare for both.

Next, learn the most widely used concept in charting: [Support and Resistance](https://learn.tradelabsai.com/price-action/support-and-resistance/).

## Continue learning

- Next lesson: [Support and Resistance](https://learn.tradelabsai.com/price-action/support-and-resistance/)
- Previous lesson: [Impulse and Correction](https://learn.tradelabsai.com/price-action/impulse-and-correction/)
- Related: [Impulse and Correction](https://learn.tradelabsai.com/price-action/impulse-and-correction/): Trends move in strong impulse legs and weaker corrective pullbacks. Learn to tell them apart, measure pullbacks and enter trends at better prices.
- Related: [Range Structure and Consolidation](https://learn.tradelabsai.com/price-action/consolidation/): Consolidation is when price moves sideways between support and resistance. Learn to identify ranges, trade them, spot breakouts and avoid range traps.
- Related: [Breakouts](https://learn.tradelabsai.com/price-action/breakouts/): A breakout is when price moves decisively beyond support, resistance or a pattern. Learn signs of a real breakout, entry methods, stops and how to avoid fakeouts.
- Related: [Bollinger Bands](https://learn.tradelabsai.com/indicators/bollinger-bands/): Bollinger Bands place bands two standard deviations around a moving average. Learn the formula, the squeeze, walking the bands, %B and common trading strategies.
- Related: [ATR (Average True Range)](https://learn.tradelabsai.com/indicators/atr/): The Average True Range measures how much an asset typically moves per period. Learn the true range formula, how to use ATR for stops, position sizing and filters.
- Related: [Volatility](https://learn.tradelabsai.com/markets/volatility/): Volatility measures how much and how fast prices move. Learn historical and implied volatility, ATR, the VIX, why volatility clusters and how it affects risk.
- Related: [Symmetrical Triangle](https://learn.tradelabsai.com/chart-patterns/symmetrical-triangle/): A symmetrical triangle has lower highs and higher lows converging to an apex. Learn why it signals compression, how to trade the breakout and avoid false moves.