Bollinger band squeeze screener for NSE

Direction is nearly impossible to predict. Volatility is not — it is the one market property with genuinely reliable structure: it clusters. Quiet days bunch together, loud days follow, and the hinge between the two regimes is tradable. The Bollinger band squeeze is the best-known way to screen for that hinge.

The mechanics

Bollinger bands sit two standard deviations either side of a 20-day average, so their width is a direct reading of recent volatility — wide bands after loud weeks, narrow bands after quiet ones. A squeeze is bands unusually narrow for that stock:

where bb().width < 0.08

Width here is normalised (band spread over the middle band), so one threshold means the same thing for a ₹80 stock and an ₹8,000 one. Under 0.08, the stock's entire recent argument spans less than 8% — an argument running out of disagreement.

The premise: a contracted range is a coiled market. Sellers who wanted out are out, buyers who wanted in are in, and the next real order flow — either direction — moves price disproportionately because there is nobody left mid-range to absorb it.

The squeeze says nothing about direction

This is the most-ignored sentence in every squeeze tutorial. Compression predicts expansion, not up. Two ways to handle that:

Filter for favourable ground. The prebuilt Volatility squeeze scan requires close > sma(200) — squeezes resolving inside long-term uptrends break upward more often than not, because the pond is tilted.

Or wait for the resolution. The squeeze's exit is a signal of its own — price escaping the upper band with volume behind it:

where close > bb().upper and rel_volume > 1.5

That is the Bollinger band breakout scan. The trade-off is the standard one: the squeeze entry is early with ambiguity, the breakout entry is confirmed at a worse price. One caution on the breakout side — in a strong trend, price can ride the upper band for weeks. A close above it is the start of an expansion, not an overbought reading.

The single-bar cousins: NR7 and the narrow-range day

The squeeze measures contraction over weeks. The same logic compresses to a single session:

• NR7 — today's high-low range is the narrowest of the last seven sessions. Toby Crabel's original range-contraction setup: bracket the little bar, take whichever side breaks.
• Narrow range day — today's range under half the stock's own ATR, the "coil" in its per-stock-calibrated form.

And the other bookend — the loud day the quiet ones lead to — is the Range expansion up scan: a session twice the stock's normal size, resolved in the buyers' favour. Expansion days set the tone for what follows more often than chance allows.

Measure the premise

"Squeezes precede moves" is a testable claim, and the hit-rate replay on each scan page tests it: every session of the past year the scan matched, and the forward return distribution after. The interesting comparison is the squeeze versus the breakout over the same year — how much hit rate does confirmation buy, and how much entry price does it cost? That number, not anyone's opinion, is the answer to "which entry should I use." The rest of the compression-and-release family lives at the volatility hub.