What a satoshi is
The satoshi is bitcoin's smallest on-chain unit: 1 BTC = 100,000,000 sats, making one sat 0.00000001 BTC. It's named for bitcoin's pseudonymous creator, Satoshi Nakamoto. Because a whole bitcoin costs more than most people invest at once, wallets and exchanges increasingly display balances in sats — owning 250,000 sats sounds and works better than owning 0.0025 BTC.
Thinking in sats per dollar
Flipping the exchange rate often makes bitcoin's price easier to reason about. At $100,000 per BTC, one dollar buys 1,000 sats. If the price doubles, a dollar buys only 500 sats. Many bitcoiners track this 'sats per dollar' number the way others track the BTC price — same information, but it frames small recurring purchases in whole numbers instead of long decimals.
Units below and beyond the satoshi
On bitcoin's Lightning Network, payments can be denominated in millisatoshis (1/1000 of a sat) for routing precision, though on-chain settlement still rounds to whole sats. You may also see 'bits' (100 sats) in older wallets. For everyday conversion, BTC, sats, and your local currency are the three units that matter.
How to use this converter
Type into whichever field you know — BTC, satoshis, or dollars — and the other two recalculate as you type. First set the BTC price field to today's market price, because every dollar figure keys off that number. The tool also surfaces two derived values worth watching: how many sats a single dollar buys, and what one satoshi is worth at the price you entered.
A worked example
With BTC at $80,000, how much is 250,000 sats? Divide by 100,000,000 to get 0.0025 BTC, then multiply by the price: 0.0025 × $80,000 = $200. Going the other way, $50 at that price buys $50 ÷ $80,000 × 100,000,000 = 62,500 sats. Notice a dollar buys 1,250 sats here; if bitcoin rallied to $100,000 that same dollar would buy only 1,000 sats — which is why the 'sats per dollar' view makes a price move tangible. This framing is also why recurring buyers often set a fixed dollar amount rather than a fixed BTC amount: a steady $50 a week automatically buys more sats when the price dips and fewer when it spikes, quietly lowering the average cost of a stack over time.