A satoshi, or sat, is the smallest divisible unit of bitcoin. One bitcoin consists of a hundred million satoshis, so 1 sat = 0.00000001 BTC. The name comes from the pseudonym of Bitcoin's creator, Satoshi Nakamoto.
Where a casino player sees satoshis
- In the fee rate. Bitcoin transaction fees are usually given in sat/vB — satoshis per virtual byte. The fee does not depend on the amount but on the transaction's data size. That is why a 20-euro and a 2,000-euro transfer cost roughly the same at the same fee rate. More: mempool.
- On Lightning invoices. Lightning wallets often show amounts in satoshis, because small payments are more readable that way.
- In the casino cashier. Some casinos show a BTC balance or minimum deposit in satoshis or in mBTC (millibitcoin, 1 mBTC = 100,000 sat).
Units that get mixed up
| Unit | Value in bitcoin | In satoshis |
|---|---|---|
| 1 BTC | 1 | 100,000,000 |
| 1 mBTC | 0.001 | 100,000 |
| 1 μBTC (bit) | 0.000001 | 100 |
| 1 sat | 0.00000001 | 1 |
If the casino and the wallet use different units, a decimal-place mistake is easy to make. Before sending, always check the amount in one and the same unit.
Why the satoshi is a useful concept for a player
Crypto casino bonus terms, minimums and limits are often given in dollars, while the deposit is made in bitcoin. Thinking in satoshis helps you see how much of an amount goes on the fee: if a withdrawal fee is, say, thousands of sats and the withdrawal itself tens of thousands of sats, the cost in percentage terms is noticeable. Small, frequent withdrawals are therefore relatively expensive on the Bitcoin chain; Lightning or a stablecoin on a cheap network suits small amounts better.
The satoshi is also a reminder of exchange-rate risk: the number of satoshis in a balance does not change, but their value in euros moves with the bitcoin price. Official vocabulary: bitcoin.org vocabulary.