BTC: Daily Quote - Cumulative Standard Deviation

Bitcoin Daily Quote - Cumulative Standard Deviation was $31,258.69 on 7 Nov 2026 (latest daily value).

How much Bitcoin's daily close has varied over its whole history: the standard deviation of every close up to each day, in dollars.

Why use it. A long-run measure of the price's spread, used to build bands. How to read it. It grows as the price reaches new ranges.

Calculation. Exact definition: The expanding population standard deviation of all admitted daily closing BTC/USD quotes from the first retained day through each UTC day. Higher values mean the quotes so far are more spread out around their cumulative mean, in US dollars per bitcoin; this is dispersion of price levels, not of returns. An interior missing quote leaves all later values undefined. Day D uses the following 00:00 UTC quote; earlier quotes are retrospective closes with unknown publication time, venue and vintage, later ones keep their actual clocks, values are provisional and revisable, and the open day is a labelled partial. cumstd(a if a > 0, otherwise undefined): the population standard deviation, dividing by N, of every positive admitted ending-boundary BTC/USD quote from the first retained day through each UTC day. Computed over the full retained history before viewport selection, with existing 40-digit Decimal arithmetic.