True range
True range is a single bar's real travel: the largest of the day's high-to-low span and the distances from either extreme back to the previous close, so overnight gaps count as movement.
`true_range` measures how far a stock actually travelled in one session, gaps included. It is the largest of three spans: today's high minus today's low, the distance from today's high back to yesterday's close, and the distance from today's low back to yesterday's close. The plain high-low range misses the overnight move — a stock that gaps down 4% and then trades a tight day did not have a quiet session, and true range says so.
On its own the number is in rupees, so it means little across stocks; the useful form compares it to the stock's own average. Below `0.5x atr(14)` is a narrow-range day — the coil the Narrow range day scan looks for, on the observation that abnormally quiet sessions tend to sit just before abnormally loud ones. Above `2x atr(14)` is a range expansion — the loud day itself, with the close's direction saying which side won it.
Being a single-bar measure is both its point and its limit: one session's true range is one observation, dominated by whatever happened that day, and it says nothing about direction — a huge true range can be a surge, a collapse, or a violent round trip that closed flat. Pair it with `change` or the close's position when direction matters, and with a turnover floor in thin names, where a wide range can mean a handful of trades.
Its sibling ATR is simply Wilder's 14-bar average of this field. True range is the event — today's travel; ATR is the norm — what travel has been typical lately. Nearly every use of one involves the other: the ratio of today's true range to ATR is how a ₹50 stock and a ₹5,000 stock get compared on the same scale.
In Sift
Written as true_range — a price amount, per bar; usually compared against atr(14). A working scan — A session twice the stock's normal size, resolved in the buyers' favour:
where true_range > 2x atr(14) and change > 01
of the 500 most-traded NSE stocks match today, as of 20 Aug 2026
Scans that use it
Prebuilt scans in the library whose query reads this value — each with a hit-rate replay over the last 250 sessions.
Common questions
What is the difference between true range and ATR?
True range is one bar's measurement — the day's real travel including any gap from the previous close. ATR is Wilder's 14-bar smoothed average of that measurement, a stock's normal daily travel. Scans typically compare the two: true range below half of ATR is a compression day, above twice ATR an expansion day.
Why not just use high minus low?
Because the plain range ignores gaps. A stock that closes at 100, opens at 96 and trades between 95 and 97 shows a high-low range of 2 — but it moved 5 from yesterday's close. True range takes the previous close into account, so overnight moves count as the volatility they are.
What does a high true range day mean?
That the session travelled far more than usual — stops run, a level surrendered, news absorbed. It says nothing about direction by itself: the same reading fits a surge, a collapse, or a round trip. The close relative to the open, or the day's change, tells you which side absorbed the move.