What Is a Satoshi? Bitcoin's Smallest Unit Explained
A satoshi — usually shortened to "sat" — is the smallest unit of Bitcoin. One whole bitcoin is made up of 100 million satoshis, so a single sat is 0.00000001 BTC. It is the crypto equivalent of a penny inside a dollar, just far, far smaller.
The one-number definition
1 bitcoin (BTC) = 100,000,000 satoshis. That is one hundred million. So a satoshi is one hundred-millionth of a bitcoin, written as 0.00000001 BTC. The unit is named after Satoshi Nakamoto, Bitcoin's anonymous creator, and it was built into the system from the very beginning.
Why such a tiny unit exists
Bitcoin's total supply is capped, and a single coin can be worth a great deal. If the smallest amount you could ever own or send was one whole bitcoin, the currency would be useless for everyday-sized payments. By dividing each coin into 100 million parts, Bitcoin stays usable whether you are moving a fortune or a fraction of a cent. This kind of fine division is common across crypto — our guide to crypto units explained covers how other coins do the same thing.
How the units stack up
| Amount | In satoshis |
|---|---|
| 1 BTC | 100,000,000 sats |
| 0.01 BTC | 1,000,000 sats |
| 0.001 BTC | 100,000 sats |
| 0.00000001 BTC | 1 sat |
You will sometimes see the term "bits" too — one bit is 100 satoshis — but sats and whole BTC are by far the most common way people describe amounts.
What a satoshi is worth
A sat has no fixed value. Its worth is simply Bitcoin's current price divided by 100 million. If bitcoin is trading at $100,000, then one sat is worth one-tenth of one cent ($0.001). Because Bitcoin's price swings constantly, the dollar value of a satoshi moves constantly too. This is also why you never need to buy a whole coin — you buy a dollar amount and receive however many sats that equals.
The bottom line
A satoshi is Bitcoin's smallest slice — one hundred-millionth of a coin, named after its creator. It exists so that Bitcoin can handle both huge sums and tiny ones, and it is why you can own a meaningful amount without ever buying a full bitcoin. Counting in sats or in BTC describes the same value; only the size of the number on screen changes.
Frequently asked
What is a satoshi?
A satoshi, often shortened to sat, is the smallest unit of Bitcoin. One bitcoin is made up of 100 million satoshis, so a single satoshi is 0.00000001 BTC. It is named after Satoshi Nakamoto, Bitcoin's creator.
How many satoshis are in one Bitcoin?
There are exactly 100 million satoshis in one bitcoin. That means one satoshi equals 0.00000001 BTC. Bitcoin was designed to divide into these tiny units so it can be used for both large and very small amounts.
How much is one satoshi worth?
A satoshi's value is simply Bitcoin's price divided by 100 million. If bitcoin trades at $100,000, one satoshi is worth one-tenth of a cent. Because Bitcoin's price is highly volatile, the value of a satoshi changes constantly.
Do I have to buy a whole Bitcoin?
No. Because Bitcoin divides into 100 million satoshis, you can buy a tiny fraction of a coin. On most platforms you buy a dollar amount and receive whatever fraction of a bitcoin that equals, measured in satoshis.
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