Bitcoin glossary
Price × circulating supply — the headline size metric, with caveats.
Market capitalization multiplies the current price by the circulating supply — for Bitcoin, price times roughly 20 million coins. It is the standard yardstick for comparing Bitcoin to companies, gold, or fiat money supplies.
The caveats: not every coin is liquid (millions are lost forever), and cap moves with the marginal trade, so it overstates what could actually be sold at the current price. Useful for scale, misleading for precision.
The live number
Bitcoin vs the dollar, at parity