Trend / stop system

PSARParabolic SAR

Q: What is PSAR used for?

Primarily as a trailing stop in confirmed trends. Wilder originally designed it as a stop-and-reverse system, but most modern traders use it only for managing existing trend trades, not for entries.

Q: Why does PSAR whipsaw in ranges?

PSAR is a trend system. In ranging markets, it constantly flips between bullish and bearish modes as price bounces between support and resistance. Every flip generates a losing signal. The whipsaw rate in ranges typically exceeds 70%.

Q: What is the acceleration factor?

The "AF" controls how quickly PSAR tightens to price. Starts at 0.02 (loose), increases by 0.02 each time a new extreme is set, capped at 0.20 (tight). The default values are Wilder's originals.

Q: How do I avoid PSAR whipsaws?

Filter with ADX. Only take PSAR signals when ADX is above 25 (strong trend). This eliminates the bulk of false signals while preserving the useful ones. Some traders also require an EMA confirmation (price above 50 EMA for longs).

Q: Is PSAR a leading or lagging indicator?

Lagging. PSAR is derived from price + an accelerating factor. It confirms trend direction after it has already started. Use it for management, not prediction.

Parabolic SAR plots dots above or below price that flip sides when the trend changes. Originally designed by Wilder as a stop-and-reverse system — useful for trailing stops in confirmed trends.

0.02 (step), 0.20 (max)

Default period

Dots above/below price

Range

N/A (price-relative)

Signal levels

Trailing stops in confirmed trends

Best use

What is PSAR?

Parabolic SAR ('Stop And Reverse') was introduced by Wilder in 1978 alongside RSI, ATR, and ADX. The indicator plots a series of dots above or below price. When the dots are below price, the trend is up; when above, the trend is down. When price crosses the dots, the indicator 'flips' to the other side, signaling a trend reversal.

PSAR was designed as a complete trading system: enter on the flip, stop where the dots are, reverse on the next flip. In practice, the system whipsaws in choppy markets, so modern use treats PSAR primarily as a trailing-stop tool in confirmed trends.

Category: Trend / stop system
Default settings: 0.02 (step), 0.20 (max)
Signal range: Dots above/below price
Introduced by: J. Welles Wilder Jr., 1978

How PSAR works

PSAR uses an accelerating factor:

SAR (new) = SAR (prior) + AF * (EP - SAR (prior))

EP = Extreme Point (highest high in uptrend or lowest low in downtrend) AF = Acceleration Factor (starts at 0.02, increases by 0.02 each time a new EP is set, capped at 0.20)

The accelerating factor causes the dots to creep closer to price as a trend matures, tightening the implied stop. In a fresh trend, PSAR is loose; in a mature trend, PSAR tracks price tightly. This makes it useful for letting winners run while still protecting accumulated profit.

How to use PSAR

Two practical uses.

1. Trailing stop in trends: After entering a trend with another signal (EMA pullback, MACD crossover, structure break), use PSAR as a trailing stop. The dots tighten automatically as the trend matures.

2. Trend confirmation with ADX: Only use PSAR signals when ADX is above 25 (strong trend). In ranging markets (ADX < 20), PSAR flips constantly and produces only losses. ADX as a filter makes PSAR much more useful.

Avoid using PSAR as a primary entry signal in unfiltered markets. The whipsaw rate in ranges is catastrophic. Use it where it shines: trailing stops in confirmed trends.

Want more practical context? Look up unfamiliar terms in the forex glossary, or see how indicators stack on real charts in the trading blog.

PSAR FAQ

What is PSAR used for?

Primarily as a trailing stop in confirmed trends. Wilder originally designed it as a stop-and-reverse system, but most modern traders use it only for managing existing trend trades, not for entries.

Why does PSAR whipsaw in ranges?

PSAR is a trend system. In ranging markets, it constantly flips between bullish and bearish modes as price bounces between support and resistance. Every flip generates a losing signal. The whipsaw rate in ranges typically exceeds 70%.

What is the acceleration factor?

The "AF" controls how quickly PSAR tightens to price. Starts at 0.02 (loose), increases by 0.02 each time a new extreme is set, capped at 0.20 (tight). The default values are Wilder's originals.

How do I avoid PSAR whipsaws?

Filter with ADX. Only take PSAR signals when ADX is above 25 (strong trend). This eliminates the bulk of false signals while preserving the useful ones. Some traders also require an EMA confirmation (price above 50 EMA for longs).

Is PSAR a leading or lagging indicator?

Lagging. PSAR is derived from price + an accelerating factor. It confirms trend direction after it has already started. Use it for management, not prediction.

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