Bollinger %B: formula and how to read it

Where the price sits between its Bollinger bands: 0% is the lower band, 100% the upper. The latest close minus the lower Bollinger band, divided by the distance between the bands. The bands sit two standard deviations either side of the 20-day average. Above 100% the close is above the upper band and below 0% it is under the lower band.

Stock Meadow groups it under Price trend.

%B = (latest close − lower band) ÷ (upper band − lower band); bands = 20-day average ± 2 standard deviations

With a lower band of $90 and an upper band of $110, a close of $105 gives %B = (105 − 90) ÷ (110 − 90) = 75%. The numbers are made up for illustration.

0% is the lower band, 50% the average, and 100% the upper band. Above 100% the close is above the upper band and below 0% it is under the lower band. It is a filter only, because neither end is better.

It can be used as a filter and as a column, but not for scoring: it describes a company rather than making it better or worse.

• A close above the upper band is not a signal to sell: in strong trends prices ride along the band.
• The bands widen and narrow with volatility, so the same percentage means different dollar moves at different times.
• Blank when the price did not vary over the 20 days.

How Stock Meadow handles gaps. Usually blank when there are fewer than 20 days of prices, or the price did not move at all.

Treat any single metric as one clue, and read the company's financial statements before drawing a conclusion. Stock Meadow's figures are research tools based on reported data, not investment advice.

No scoring model uses it. It is a filter and a table column only.

Read about every scoring model in How scores work.

• Bollinger Band Width: how wide the Bollinger bands are compared with the price; narrow means quiet.
• Stochastic Oscillator (%K): where the close sits in the last 14 days' range, from 0 to 100.
• Relative Strength Index (RSI): recent buying momentum; 50–70 is healthy.

What does %B above 100% mean?

It means the close is above the upper Bollinger Band, more than two standard deviations above the 20-day average. That happens in strong rallies and is relatively unusual.

Can I score stocks on Bollinger %B?

It can be used as a filter and as a column, but not for scoring: it describes a company rather than making it better or worse.

Why is Bollinger %B blank for some stocks?

It is usually blank when there are fewer than 20 days of prices, or the price did not move at all. Stock Meadow leaves the figure blank rather than guessing it.