A satoshi is the smallest unit of bitcoin recorded on the main ledger: one hundred-millionth of a bitcoin, or 0.00000001 BTC. Every balance and transaction on the network is, underneath, a whole number of satoshis. For a finance team, the satoshi matters for one practical reason: systems that hold fewer than eight decimal places will not reconcile exactly with the ledger.
What is a satoshi and where the name comes from
The unit is named after Bitcoin's pseudonymous creator, Satoshi Nakamoto. It is often shortened to "sat" or "sats".
The software does not store fractions of bitcoin. It stores integers of satoshis. What a wallet displays as 1.5 BTC is recorded as 150,000,000 satoshis.
Bitcoin's units at a glance
| Unit | In BTC | In satoshis | Where you will see it |
|---|---|---|---|
| Bitcoin (BTC) | 1 | 100,000,000 | Prices, trade sizes, balances |
| Millibitcoin (mBTC) | 0.001 | 100,000 | Occasionally in older software |
| Microbitcoin (μBTC, "bits") | 0.000001 | 100 | Rarely, in some consumer apps |
| Satoshi (sat) | 0.00000001 | 1 | Fees, small payments, technical records |
| Millisatoshi (msat) | 0.00000000001 | 0.001 | Lightning Network only |
Two points for treasury teams:
- Network fees are quoted in satoshis per virtual byte, so fee reports will use this unit. See how Bitcoin network fees work.
- Millisatoshis exist only on the Lightning Network, which tracks amounts below one satoshi internally but settles to whole satoshis on the main ledger. See what is the Lightning Network.
Why divisibility matters
Bitcoin's supply is capped at 21 million coins, or 2.1 quadrillion satoshis. The cap is sometimes misread as a practical limit on use. It is not: divisibility to eight decimal places means a company can buy, hold or pay any amount it needs.
It also corrects a common misconception from first conversations: there is no need to buy a whole bitcoin. A company can hold 0.25 BTC, or 250.12345678 BTC.
Precision in finance systems
This is where the satoshi becomes a real operational issue. Many ERP, treasury and consolidation systems default to two, four or six decimal places for quantities. Bitcoin needs eight.
If a system rounds quantities:
- Holdings in the general ledger will not match the custodian statement or the public ledger exactly.
- Small differences accumulate across many transactions and fees.
- Cost basis per unit can be distorted, affecting gains and losses. See cost basis methods.
- Auditors will ask for explanations of every unreconciled difference.
What to set up before the first purchase:
- Quantity fields at eight decimal places, in BTC, in every system that holds Bitcoin quantities.
- A single unit convention. Record in BTC, not a mix of BTC and satoshis. Convert fee data from providers on the way in.
- Rounding rules for currency values. Fair value in reporting currency is usually rounded to two decimals, but quantity should never be rounded.
- Rate precision. Store the price used for valuation at sufficient precision, and document its source.
- Reconciliation tolerance. Set it to zero for quantity. Any difference is a break to investigate.
Ask your ERP or treasury system team to test-post a purchase of 1.23456789 BTC and a fee of 0.00001234 BTC before go-live. If either is rounded anywhere, fix the configuration before real money moves.
Satoshis in execution and settlement
In OTC trading, prices are quoted per whole bitcoin, but settlement quantities run to eight decimals. Execution reports should show:
- Quantity to eight decimals.
- Price per BTC.
- Gross and net consideration, with any spread or fee shown separately.
- Network fee in BTC, if deducted from the amount delivered.
See what a Bitcoin execution report should contain.
Dust and very small balances
Outputs worth only a few hundred satoshis can cost more in fees to spend than they are worth. These are called dust. Some wallets refuse to create them.
For a corporate treasury, dust is mostly a housekeeping issue. It can arise from change outputs or from unsolicited tiny deposits, which are sometimes sent to track or trick wallet holders. Good practice is not to spend unsolicited dust, and to note small balances in reconciliations rather than chase them.
There are two reasons for caution. Spending dust alongside the company's own outputs can link addresses together on the public ledger, weakening privacy. And unsolicited deposits from unknown sources can raise screening questions. A simple rule in the operating procedures, such as "do not consolidate unsolicited deposits below a set amount without compliance review", removes the need for judgement calls by individual staff.
A related point concerns reporting. Board and management reports normally show holdings in BTC to a sensible number of decimals, often two or four, with the full eight-decimal figure kept in the ledger and reconciliation file. That is a presentation choice, not a recording choice. State it in the reporting notes so that readers know the displayed figure is rounded while the books are not.
Recording the satoshi in the books
The accounting does not change because amounts are small. Each acquisition and disposal is recorded at its quantity and value. Fees paid in bitcoin are disposals of a small quantity, and the treatment depends on the framework and facts. See Bitcoin journal entries, and take your own accounting and tax advice.
How The Bitcoin World helps
We help finance teams prepare systems, unit conventions and reconciliation rules before their first Bitcoin purchase, so that records match the ledger from day one. Execution and custody are carried out by licensed third-party institutions. Unit definitions are also in our glossary.