What Is ATR? Average True Range Formula, Indicator & Stop Loss Strategy
Praveen Dubey (SEBI Registered RA)
SP RESEARCHVIA PVT. LTD. (INH000015808)
The Average True Range (ATR) is a technical volatility indicator developed by J. Welles Wilder Jr. that quantifies market volatility by decomposing the entire range of an asset price for a given period. Unlike directional indicators, ATR does not forecast whether prices will rise or fall; it strictly measures price volatility in absolute points or rupees.
Understanding True Range (TR): Why High Minus Low Is Insufficient
In simple range calculations, volatility is measured as High - Low. However, this formula fails when markets gap open above or below the prior day's close—a frequent event on the Nifty 50 due to overnight global developments.
To capture full price dispersion, Wilder formulated the True Range (TR) as the greatest of three mathematical distances:
By measuring from the prior close, True Range accurately accounts for overnight gap-ups and gap-downs that would otherwise be invisible in standard intraday candle heights.
The 14-Period ATR Calculation
After determining daily True Range values, the ATR is computed as a 14-period smoothed moving average using Wilder's proprietary smoothing:
Wilder's ATR Formula:
Current ATR = [ (Prior ATR × 13) + Current TR ] / 14
If the Nifty 50 has a 14-day daily ATR of 220 points, it indicates that the index typically moves an average of 220 points from high to low across a single trading session. ATR values are quoted in points, rupees, or dollars—never in percentage terms.
ATR Stop Loss Strategies: Escaping the Fixed-Percentage Trap
Retail traders frequently use arbitrary fixed percentage stop losses (e.g., placing a rigid 1% stop on every stock). In low-volatility consumer staples, a 1% stop may be too wide; in high-beta metal or mid-cap stocks, a 1% stop is smaller than normal random intraday noise and gets routinely hunted.
ATR stop losses adapt dynamically to the asset's current volatility regime:
Initial Stop Loss Placement Example
Suppose an equity stock trades at ₹1,500 with a daily ATR of ₹25. An investor initiating a long swing position using a common 2.0× ATR buffer would calculate their protective stop as:
Stop Loss = ₹1,500 - (2.0 × ₹25) = ₹1,500 - ₹50 = ₹1,450.
This ₹50 buffer allows the stock to absorb standard two-sigma daily oscillations without prematurely triggering an exit. Review our detailed guide on stop loss order placement.
Trailing Chandelier Exit Strategy
As a stock advances in a trend, the stop loss should trail behind price progress. The classic Chandelier Exit sets the trailing stop at:
Trailing Stop = Highest High Since Entry - (2.5 × ATR).
The stop level ratchets upward as new price highs are established, locking in unrealized gains while giving the trend breathing room.
Position Sizing: Standardizing Rupee Risk Across Assets
The ultimate application of ATR lies in position sizing. Review our core framework on position sizing and risk management for the 1% risk rule.
ATR Position Sizing Equation:
Shares to Buy = Maximum Rupee Risk / (ATR Multiplier × ATR)
Example: If your trading account risk limit is ₹10,000 per trade, and a stock's 2x ATR stop distance is ₹40 per share, you buy: ₹10,000 / ₹40 = 250 shares. If volatility rises and the ATR distance doubles to ₹80, your lot size automatically scales down to 125 shares, preserving identical rupee risk.
Frequently Asked Questions: ATR Indicator
What does Average True Range (ATR) measure?
Average True Range (ATR) measures market volatility by decomposing the total trading range of an asset across a specified timeframe. It does not measure or predict price direction; it strictly quantifies the typical price movement in absolute points or rupees.
How is True Range (TR) calculated?
True Range is the greatest of three values: (1) Current High minus Current Low, (2) Absolute value of Current High minus Previous Close, and (3) Absolute value of Current Low minus Previous Close. This incorporates overnight gap openings.
How is ATR used to set stop losses?
Traders place volatility-adjusted stop losses by subtracting a multiple of ATR (such as 1.5x, 2.0x, or 3.0x ATR) from their entry price for long trades, ensuring that normal market noise does not trigger premature exits.
Is a 2x ATR stop loss universally optimal?
No single multiplier is universally optimal. Short-term intraday traders often use 1.0x to 1.5x ATR stops to control risk, while multi-week swing traders often use 2.0x to 3.0x ATR stops to absorb broader price swings. Multipliers must be adapted to strategy and timeframe.
How does ATR help in position sizing?
ATR helps calculate position size by dividing the maximum rupee risk per trade by the ATR stop-loss distance in points, ensuring that the trader risks a consistent rupee amount regardless of whether market volatility is high or low.
Written by Praveen Dubey
Chief Research Analyst | SEBI Reg: INH000015808
Statutory Warning & Risk Disclaimer: Investment in securities market is subject to market risks. Read all related documents carefully before investing. Registration granted by SEBI and certification from NISM in no way guarantee performance of the intermediary or provide any assurance of returns to investors. Content provided on this blog is for informational and educational purposes only.