Pineify logo
Derived Bollinger indicator

Bollinger Bands %B: turn price location into one testable number

Bollinger Bands %B measures price location inside or outside the bands. The lower band equals 0, the middle band equals 0.5, and the upper band equals 1 when the standard decimal formula is used.

Generate the %B scriptCalculate the bands

Direct answer

%B = (price - lower band) / (upper band - lower band). Values above 1 place price above the upper band, while values below 0 place it below the lower band. That location is not a reversal forecast.

Starting values

Lower band

%B = 0

Middle band

%B = 0.5

Upper band

%B = 1

Above upper band

%B > 1

How I test the setup

  1. 1

    When I compare %B across SPY and QQQ, I use decimal values in both scripts. Some platforms display the same number as 0 to 100.

  2. 2

    I record the Bollinger length and multiplier with every %B threshold. A value of 0.8 depends on the bands that produced it.

  3. 3

    I test a cross and a level as different events. Closing above 0.8 is not the same rule as crossing 0.8 from below.

The %B formula

Subtract the lower band from the current price, then divide by the full distance between the upper and lower bands. If a platform multiplies the result by 100, the same reference points become 0, 50, and 100.

  • %B = (current price - lower band) / (upper band - lower band).
  • %B of 0.25 places price one quarter of the way up from the lower band.
  • %B of 1.10 places price above the upper band by one tenth of the band range.

Use %B as a precise condition, not a label

A chart can make near-band readings hard to compare. %B turns that position into a series that can be screened, alerted, and backtested. Define whether your rule uses a level, a crossover, consecutive closes, or a trend filter before testing it.

What %B does not tell you

A value above 1 does not automatically mean sell, and a value below 0 does not automatically mean buy. Strong trends can keep price near or beyond an outer band. Pair any re-entry rule with trend context, a stop condition, and realistic costs.

Common %B reference values

Price locationDecimal scalePercentage scale
Below lower bandLess than 0Less than 0%
At lower band00%
At middle band0.550%
At upper band1100%
Above upper bandGreater than 1Greater than 100%

Bollinger %B Pine Script prompt

This version exposes both the formula and the threshold direction.

Create a Pine Script v6 indicator for Bollinger Bands %B. Use close, length 20, and multiplier 2. Calculate percentB = (close - lowerBand) / (upperBand - lowerBand). Plot 0, 0.5, and 1 reference lines. Add bar-close alerts for crossing above 0.8, crossing below 0.2, crossing above 1, and crossing below 0. Keep each alert separate and guard against division by zero.
Generate the %B script

Related Bollinger Bands pages

Bollinger Bands calculatorCalculate the upper, middle, and lower values used by %B.Modified Bollinger BandsInspect Pine Script for a modified %B-style indicator.Bollinger BandWidthMeasure band width instead of price location.Bollinger Bands crossoverTurn band and %B crossings into explicit bar-close events.

Tools for the next test

Bollinger Bands Calculator

Compute Bollinger Bands to analyze market volatility and potential price breakouts.

Try it

Bollinger Bands Crossover

Define upper, lower, and basis crossover events by direction and generate separate bar-close alerts for each event.

Try it

Bollinger Bands and RSI

Combine Bollinger price location with a separate RSI momentum condition and inspect the resulting Pine Script rules.

Try it

Sources and method notes

Bollinger Bands %bTradingView Help CenterTradingView documents the decimal formula and the 0, 0.5, and 1 reference values.Percent B (%B)Fidelity Learning CenterFidelity shows the percentage-scale formula and explains values outside the bands.

Pineify is an information tool, not investment advice. %B measures price location and does not guarantee a reversal, continuation, or return.

Common questions