Reviewed and updated: October 19, 2026.
Ordinals, inscriptions, BRC-20 and Runes refer to different systems built around Bitcoin transactions. Calling all four Bitcoin NFTs hides the most important distinction: some identify individual satoshis or content, while others define fungible token balances through additional interpretation rules.
Four concepts, four questions
| Concept | Main role | Question to ask |
|---|---|---|
| Ordinal theory | Number and track individual satoshis | Which satoshi is being followed? |
| Inscription | Associate content with a satoshi using transaction data | Which inscription and content are represented? |
| BRC-20 | Interpret specified inscriptions as fungible-token operations | Which rules determine the indexed balance? |
| Runes | Represent fungible tokens with balances assigned to transaction outputs | Which outputs carry the balances under Rune rules? |
The Ordinal Theory Handbook describes numbering in mining order and transfers based on input/output order. It does not require a new Bitcoin consensus rule. Inscriptions are content-bearing records; they should not be confused with a new supply of bitcoin or with every other token protocol that uses Bitcoin.
Correcting the unit calculation
One bitcoin contains 100 million satoshis. Multiplying the commonly stated 21 million bitcoin limit by 100 million gives 2,100,000,000,000,000 satoshis: 2.1 quadrillion, not 2.1 trillion. This is the arithmetic of that rounded supply ceiling. It is not a count of satoshis currently mined, recoverable or available for sale; actual issuance and spendability need their own treatment.
Collector descriptions such as rare refer to a classification or market convention. They do not change a satoshi's face value in Bitcoin's accounting. A buyer paying a premium is making a separate valuation judgment, and a rarity label does not guarantee another buyer.
BRC-20 balances need an interpretation layer
Domo's original BRC-20 experiment describes deploy, mint and transfer inscriptions whose processing produces balances outside Bitcoin's native asset accounting. It is a historical design source, not a complete specification for every later extension or current service. An ordinary Bitcoin node can accept a transaction without enforcing every BRC-20 rule an indexer applies.
For a simplified example, assume an indexer recognizes 100 valid units minted to an address and a completed valid transfer of 25 units away. Its resulting token balance is 75. This does not mean the address holds 75 BTC or 75 spendable satoshis. The Bitcoin inputs, outputs and transaction fee remain a separate accounting system. The example omits protocol-specific validity and transfer stages.
How Runes differs
The Runes documentation describes etching, minting and transferring fungible tokens, with balances assigned to UTXOs and messages carried in runestones. It also describes malformed messages that can burn balances. Its specification page explicitly identifies the implementation as normative; an informal summary should not be used to construct a real transfer.
A compatible wallet therefore needs to handle more than an address and a BTC amount. It must identify the relevant outputs and follow the token protocol's rules. Sending a transaction that is valid for Bitcoin does not guarantee that a token operation is interpreted as intended.
A practical verification checklist
- Identify the exact asset and protocol. Tickers and collection names can be duplicated.
- Check the wallet and marketplace support the same protocol and relevant rule version.
- Inspect the inscription ID or Rune identifier and the outputs involved.
- Separate the item price, marketplace charge and network fee.
- Review the receiving wallet's ability to display and later transfer the asset.
- Check what intellectual-property rights, if any, accompany the purchase.
Do not infer adoption or miner revenue from a single busy block. Those claims need a dated dataset and a method that separates token activity from other transactions. This guide explains the accounting layers; it does not provide a current token ranking, market forecast or assurance of liquidity.
Sources and scope
- Ordinal Theory Handbook: overview
- Domo: original BRC-20 experiment (historical reference)
- Ordinal Theory Handbook: Runes
- Runes specification and implementation authority
Continue reading: How inscription data is stored · Bitcoin transactions and UTXOs
Editorial update: Corrected trillion to quadrillion; removed unsupported BRC-20 upgrade and adoption claims; distinguished inscription, indexer and UTXO-based token accounting with a worked balance example.