BTC Bollinger Bands: $79,676.63
Bitcoin's price inside a stretchy channel: the 20-day average price in the middle, with an upper and lower edge that widen when the price swings and pinch together when it goes quiet. The bars at the bottom show how wide the channel is, as a percentage.
Three lines around the price. The middle one is the average closing price of the last 20 days.
The upper and lower edges sit two typical daily swings **above** and **below** it, so the channel automatically gets wider in wild markets and narrower in calm ones.
A wide channel means the price has been swinging hard; a pinched channel means it has gone quiet. For example, a bottom bar reading 0.06 means the two edges are about 6% apart — very tight for Bitcoin, and every long quiet stretch in its history has ended in a sharp move, though nothing here tells you which direction.
The price touching the upper edge means it has travelled unusually far up in a short time; it **does not** mean it has to come back.
In words: the middle line is the average closing price of the last 20 days, and the two edges sit two typical swings **above** and below it. The bottom bars are the gap between the edges divided by the middle line [4 standard deviations ÷ 20-day average] — always a percentage of the price, **never** a dollar amount.
The lower edge is held at $0.01, because in Bitcoin's wildest early months the calculation produces a negative price, which **cannot** be drawn — this affects **only** a handful of 2011 points. Everything is built from daily closing prices, so swings that happened and reversed inside a day are invisible here.
Our own full BTC price history (btc_price_daily: blockchain.info daily closes, 2010-08 to today, 5800+ points). No external API at request time.
Own compute · full BTC price history 2010+ (no external API)