Bollinger Bands calculator
Paste a list of closing prices to get the upper, middle and lower Bollinger Bands, plus %B and bandwidth, for any period and width. Works for forex, crypto or shares. Free, no sign-up, nothing leaves your browser.
20 prices read; the bands use the last 20. This is a calculator, not advice.
What Bollinger Bands are
Bollinger Bands, created by John Bollinger, wrap a price chart in three lines: a middle band that is the 20-period simple moving average, and upper and lower bands two standard deviations above and below it. When prices swing about a lot the bands widen; when the market is quiet they squeeze together.
How traders read them
A close near the upper band means price is high compared with its recent range, and near the lower band means it is low. Some traders watch for a squeeze, when the bands are unusually narrow, as a sign a bigger move may follow. Touching a band is not a signal on its own: in a strong trend price can ride along one band for a long time.
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