Crypto glossary

Satoshi

A satoshi, or sat, is the smallest unit of Bitcoin recorded on the blockchain: one satoshi equals 0.00000001 BTC, so one bitcoin is 100 million sats.

Auf Deutsch lesen

Where the name comes from

The unit is named after Satoshi Nakamoto, the pseudonymous creator of Bitcoin, who published the white paper in 2008 and launched the network in January 2009. The name was adopted by the community; the original software simply tracked amounts as whole numbers of this smallest unit.

Internally, Bitcoin never deals with fractions at all. Every balance and every transaction output is stored as an integer number of satoshis. BTC with eight decimal places is just a more convenient way to display it.

Converting between BTC and sats

The math is fixed: 1 BTC = 100,000,000 sats, 0.001 BTC = 100,000 sats, and 0.00001 BTC = 1,000 sats. Because the total supply is capped near 21 million BTC, there will never be more than about 2.1 quadrillion satoshis.

Where you see sats in practice

Transaction fees are usually quoted in satoshis per virtual byte (sat/vB), which reflects how much block space a transaction uses. Wallets often let you switch the display to sats, and the Lightning Network, Bitcoin's payment-channel layer, handles even smaller amounts internally, called millisatoshis, though only whole sats settle on-chain.

Many people prefer thinking in sats because it avoids awkward decimals. Buying 50,000 sats feels more natural than buying 0.0005 BTC, and it makes clear that you do not need to buy a whole bitcoin.

A common mistake

Mixing up decimal places can be costly. Sending 0.01 BTC instead of 0.001 BTC is a tenfold error, and on-chain transactions cannot be reversed. Double-check the unit your wallet is showing before you confirm a payment. A useful habit is to send a small test amount first when using a new address, and to compare the amount in both BTC and sats if your wallet can display both.

Ask Coach about it

Coach is the AI on AtenaCrypto. It explains crypto with live market data, in plain words.

How are Bitcoin transaction fees calculated in satoshis per virtual byte?Ask Coach →

Frequently asked questions

How many satoshis are in one bitcoin?

Exactly 100 million. One satoshi is 0.00000001 BTC.

Can I buy less than one bitcoin?

Yes. Bitcoin is divisible down to one satoshi, so you can hold any amount that is a whole number of sats.

What does sat/vB mean?

It is a fee rate: satoshis paid per virtual byte of transaction size. A higher rate usually gets a transaction confirmed sooner.

Learn it step by step

AC Learning explains these ideas in interactive lessons — the first eight sections are free.

Open AC Learning → Create a free account

All glossary terms · Educational reference only — not investment, legal, tax or financial advice.