Introductory Context
"The True Range accounts for overnight gaps, which is why it is called 'true' range rather than simply High minus Low. When a market gaps significantly overnight, the simple session High minus Low would understate the actual range experienced by participants holding positions. By also measuring the distance between the prior close and the current High, and between the prior close and the current Low, the True Range captures the full gap-inclusive range of price movement. "
ATR Calculation -- Why It Includes Gaps
The True Range for any session is the largest of three values: the current session's High minus the current session's Low (the standard day's range), the absolute value of the current High minus the prior session's Close (the upward gap plus the day's high from that gap), and the absolute value of the current Low minus the prior session's Close (the downward gap plus the day's low from that gap). The ATR is then the 14-period exponential moving average of these daily True Range values.
ATR Formula
True Range = Maximum of: (Current High - Current Low), |Current High - Prior Close|, |Current Low - Prior Close|. ATR(14) = 14-period exponential moving average of daily True Range. For Nifty, typical ATR ranges: Low volatility period: 100 to 150 points. Normal volatility: 150 to 250 points. High volatility (events, global stress): 300 to 500+ points. For Bank Nifty (higher absolute volatility): multiply the above by approximately 2 to 3 times.
ATR for Stop-Loss Placement
The most direct and most important application of ATR for options traders is calibrating the stop-loss distance. A stop placed too close to the entry will be triggered by normal intraday volatility before the trade has had time to develop. A stop placed too far away exposes more capital to risk than the 2 percent rule permits. ATR-based stops calibrate the stop distance to the actual current volatility of the instrument.
The standard ATR-based stop formula: stop distance = 1.5 x ATR(14). If Nifty's current 14-day ATR is 200 points, the stop for a call entry at the 50 EMA is placed 300 points (1.5 x 200) below the entry. This distance accommodates typical intraday volatility (one ATR worth of movement) plus a safety buffer (the additional 0.5 ATR) without being so wide that a genuine trend failure is absorbed without exit.
ATR-Based Stop vs Chart-Based Stop -- Use Both
The ATR-based stop (1.5 x ATR) and the chart-based stop (below the support level that defined the entry) should be checked together. Use whichever is further from the entry -- not whichever is closer. If the support level is 150 points below the entry and the 1.5 x ATR stop is 300 points below the entry, use the 300-point stop. If the support level is 350 points below the entry and the ATR stop is 200 points below, use the 350-point stop. The wider stop accommodates both normal volatility AND respects the analytical level. Never set a stop so tight that normal ATR-sized moves trigger it before the setup has had time to develop.
ATR for Target Feasibility Assessment
Before entering any options position, the target must be assessed for feasibility: can the underlying realistically reach the target within the available expiry window? The ATR provides the statistical framework for this assessment.
The expected one-standard-deviation move over N sessions = ATR x square root of N. This approximation (from random walk statistics) gives a reasonable estimate of the expected price range for N sessions given current volatility. If your target is 400 points away and you have 10 sessions until expiry, the expected one-sigma move is ATR x sqrt(10) = 180 x 3.16 = 569 points. Your 400-point target is well within the one-sigma range -- achievable with reasonable probability. If your target is 700 points away in 10 sessions with ATR of 180, the target is 1.23 sigma (700/569) -- still feasible but at the higher end of the expected range.
ATR is the market's official volatility report, updated every session. Before you set a stop or assess a target, check the ATR. A stop appropriate for an ATR of 150 is dangerously tight when ATR is 300. The market does not adjust to your pre-planned stop. Your stop must adjust to the market's current behaviour.
ATR for Expiry Selection -- The Time Requirement Calculation
The ATR-based expected move calculation provides direct guidance for expiry selection. If the technical target is 600 points away and the current ATR is 200 points: expected sessions to target = (target distance / ATR)^2 = (600/200)^2 = 9 sessions. The option expiry should provide at least 1.5 times this estimate = 13 to 14 sessions minimum. Select the expiry that gives at least 13 to 14 sessions from today.
This ATR-based expiry calculation prevents both underbuying (selecting a weekly expiry for a target that requires two weeks) and overbuying (selecting a three-month expiry for a one-week target and paying unnecessary time value). The calculation ties the expiry directly to the actual current market volatility rather than to an intuitive guess about how long the move will take.
ATR Changes Significantly Around Major Events
India VIX and Nifty ATR both spike dramatically around major events -- Union Budget, RBI policy days, election results. An ATR of 180 in a normal week can become 350 or more in event weeks. This ATR expansion affects two things: your stop must widen (1.5 x 350 = 525 points stop instead of 270) AND your premium cost rises (higher VIX makes options more expensive). For event-week options, recalculate the ATR on the day of entry using current data rather than last week's ATR. The stop distance may need to expand significantly to accommodate the elevated event-week volatility.
ATR Comparison Across Instruments
ATR is the universal volatility comparison tool across different instruments. Bank Nifty's ATR is typically 400 to 700 points when Nifty's ATR is 150 to 250 points. This 2.5x to 3x ratio of Bank Nifty to Nifty ATR means: Bank Nifty stops must be wider in absolute point terms, Bank Nifty targets require proportionally larger moves to justify the premium, and Bank Nifty options positions require larger absolute premium per lot (which raises the minimum capital requirement discussed in Topic 8.14).
For a trader switching between Nifty and Bank Nifty options, ATR recalibration is essential. The intuition built on trading Nifty -- where a 200-point stop feels reasonable -- would produce stops that are far too tight on Bank Nifty, where 400 to 500 points of intraday movement is normal in an active session. Always check ATR for the specific instrument before entering any position.
Display ATR as a Separate Panel Below Your Chart
Add the ATR(14) indicator as a separate panel below your Nifty daily chart in TradingView or Zerodha Kite. The current ATR value is displayed numerically in the indicator panel. Each Sunday evening analysis session: note the current ATR and use it to calculate the stop distance (1.5 x ATR) and to verify target feasibility (ATR x sqrt of sessions to expiry). Write the ATR value in your trading journal at the top of each weekly analysis entry. This habit ensures you are always working with current volatility data, not relying on memory or assumption.