Satoshi / BTC Converter

Bitcoin does not divide into cents but into satoshis. One bitcoin is exactly 100,000,000 satoshis, and the satoshi is the smallest unit the protocol has: there is nothing below it on-chain. The name comes from its creator's pseudonym and caught on as prices rose and everyday amounts became awkward to write in BTC.

Between those two extremes sit practical intermediate units. The bit, also called a microbitcoin, is 100 satoshis. The millibitcoin or mBTC is 100,000 satoshis, one thousandth of a bitcoin. Neither appears in the protocol: they are interface conventions used by some wallets and exchanges to show small amounts without a row of zeros.

Every conversion in this tool runs on big integers over satoshis, not floating-point numbers. That matters more than it sounds: in floating point, 0.1 + 0.2 does not equal exactly 0.3, and that class of error compounds precisely when you work with eight decimal places. Here 1 BTC is exactly 100,000,000 satoshis, and 21,000,000 BTC is exactly 2,100,000,000,000,000 satoshis, with no dust lost along the way.

For the same reason, the tool rejects amounts with more precision than the unit can represent instead of quietly truncating them. Type 0.000000001 BTC, which is a tenth of a satoshi, and you get an explicit error: better than a converter handing back a rounded figure and letting you believe the amount was possible. The price field is the only part that uses floating point, because the price itself is an approximate market value.