Bitcoin ($BTC ) is a decentralized digital currency. It uses blockchain, which is a distributed ledger secured by cryptographic techniques. Bitcoin was introduced to the public in 2008 by an anonymous developer or group of developers using the name Satoshi Nakamoto. It has since become the most well-known and largest cryptocurrency in the world. Its popularity has inspired the development of many other cryptocurrencies. Bitcoin is frequently compared to other physical stores of value, with the added functionality of being transferable in digital form. It is commonly used as a medium of exchange, a digital representation of ownership, or a unit of account. Bitcoin hit its all-time high of $109,026.02 on January 19, 2025. Bitcoin currently has a circulating supply of 19,861,040, which is 95% of its max supply (21,000,000 BTC) and 100% of its total supply (19,861,040). The market cap is $1.88T, calculated by multiplying Bitcoin's current price of $94,647.86 by its total supply of 19,861,040 BTC.