24h (24 hours) is a label on cryptocurrency price and market-data sites for figures measured over the most recent rolling 24 hours. It is the default window for the headline percentage price change, for trading volume, and for the day's high and low. Unlike a stock exchange, crypto markets trade around the clock, so there is no official open or close; the 24h figure simply compares now with the same moment one day earlier, using timestamps in UTC. The rolling design means a sharp move drops out of the 24h change exactly a day later, which can make the number jump even when the price is flat. Reported 24h volume can also be inflated by wash trading on some venues. Also see 1h (1 Hour) and 7d (7 Days).