Technical analysis

Bollinger %B

How many standard deviations price sits from its own 20-day average.

Why it matters

Bollinger bands are the 20-day average plus and minus two standard deviations. This number says where price sits inside that structure, and its virtue is that it adapts on its own: when the market is quiet the bands narrow and little movement is needed to reach the extremes; when it's turbulent they widen. It is, fundamentally, the same normalizing idea as MVRV Z-Score or the flow z-scores, applied to price against its own recent mean.

Build it yourself

Drag price, its average and its standard deviation, and watch how the SAME dollar distance gives different readings depending on how turbulent the market is.

%B (the project variant) = (Price − 20-day average) ÷ 20-day stdev
Bollinger %B

The same value on the classic 0-to-1 scale:

Illustrative example numbers for practice — not real data.

How it's calculated, step by step

  1. The simple average of the last 20 days' price is computed, and the standard deviation of those same 20 days.
  2. %B = (today's price − 20-day average) ÷ 20-day standard deviation. There's no value until 20 days of history exist.
Coincident signal. Important compatibility warning: this is NOT the classic definition of %B. The classic one runs from 0 (lower band) to 1 (upper band); what the project computes is a pure z-score, worth 0 at the mean and ±2 at the bands. Both numbers say the same thing on different scales, and mixing them up when comparing against another tool is an easy mistake. It's documented as it is in the code, not as it "should" be.

Chart

This is real Bitcoin data, computed from the blockchain — not the illustrative example above.

Data last updated on 2026-09-09.

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