Ordinals are a numbering system that assigns a unique identity to each individual satoshi (the smallest unit of Bitcoin). Inscriptions use this system to permanently attach data (images, text, code) directly to specific satoshis on the Bitcoin blockchain. The result: NFT-like digital artifacts stored on Bitcoin itself, with no separate metadata server needed. They are as permanent as Bitcoin.
What Is a Bitcoin Ordinal / Inscription?
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The short version
Every satoshi in existence gets a serial number (its ordinal). You can then engrave data (a picture, a message, a file) onto a specific satoshi, permanently. That data lives on the Bitcoin blockchain forever, stored across every Bitcoin node worldwide. Unlike Ethereum NFTs that often point to external image servers, inscriptions ARE on-chain. If Bitcoin survives, your inscription survives.
How It Works
How ordinals work: Ordinal theory (created by Casey Rodarmor, January 2023) assigns a sequential number to every satoshi ever mined, based on the order they were created (first sat in the genesis block is ordinal 0). These numbers allow individual satoshis to be tracked, transferred, and collected. Inscriptions: using Bitcoin Taproot (SegWit v1, activated November 2021), arbitrary data can be embedded in the witness field of a transaction and associated with a specific satoshi. The data is stored in the witness discount section (4x cheaper in terms of block weight), making storage practical. Data types: images (JPEG, PNG, SVG, WebP), text (plain text, JSON), HTML/CSS/JS (interactive content), and even full applications. Size limit: practical limit is the block size (~4MB for witness data in one block, but most inscriptions are 50KB-400KB). Storage permanence: inscribed data is part of the Bitcoin blockchain permanently. Every full node stores it. It cannot be deleted, censored, or altered. This is the strongest permanence guarantee in crypto (Bitcoin has never been reorganized to remove data since its inception). BRC-20 tokens: a specific inscription format that mimics ERC-20 fungible tokens on Bitcoin. They use JSON inscriptions to define deploy/mint/transfer operations. Examples: ORDI, SATS. Not part of the original ordinals vision but emerged from the community. They are slower and less efficient than Ethereum tokens but exist on Bitcoin. Market: ordinals trade on marketplaces like Magic Eden (Bitcoin), Ordinals Market, and Gamma. The ecosystem is smaller than Ethereum NFTs but growing.
Inscribing an image onto Bitcoin
You want to permanently store a 200KB digital artwork on Bitcoin. Process: (1) Go to an inscription service (Gamma, OrdinalsBot, or run your own ord client). (2) Upload your image file (200KB JPEG). (3) The service creates a Bitcoin transaction with the image data in the Taproot witness. (4) You pay the inscription fee: approximately 200,000 bytes x current sat/vB fee rate. At 20 sat/vB: ~4M sats = ~$2,400 (expensive at high fee rates). At 5 sat/vB (quiet period): ~$600. (5) The transaction is mined. Your image is now part of Bitcoin block #XXX permanently. (6) The satoshi carrying your inscription can be transferred to any Bitcoin address. Whoever holds that satoshi holds the inscription. (7) View it on ordinals.com or any ordinals explorer by its inscription number. Your artwork now exists in every Bitcoin full node worldwide (~60,000 copies) and will persist as long as Bitcoin does. No IPFS pinning needed. No server to maintain. Pure Bitcoin permanence.
What People Get Wrong
Ordinals are bad for Bitcoin
Debated within the community. Critics say inscriptions bloat the blockchain and compete with financial transactions for block space. Supporters say they bring new users, increase miner revenue (inscription fees), and demonstrate Bitcoin flexibility. Both have merit. Structurally: inscriptions pay market-rate fees for block space like any other transaction. They do not take anything for free.
Ordinal inscriptions are the same as Ethereum NFTs
Key differences: (1) Inscriptions store data ON-CHAIN (no external server). Most Ethereum NFTs store a pointer to IPFS/HTTP. (2) No smart contract royalties (no ERC-2981 equivalent on Bitcoin). (3) No native marketplace logic (trading relies on PSBTs and off-chain coordination, not automated on-chain swaps). (4) Ordinals are built on the most secure blockchain (Bitcoin) but with less programmability.
You need special Bitcoin to use ordinals
Any Bitcoin can hold inscriptions. The ordinal number is just a conceptual label for tracking satoshis. You do not buy special Bitcoin. You send normal Bitcoin to an inscription service and it attaches data to one of the satoshis in that transaction. Your existing Bitcoin wallet (if it supports Taproot) can hold inscriptions.
Keep Reading
Sources & Further Reading
- Ordinals Protocol
Official ordinals explorer for browsing inscriptions by number
- Magic Eden Bitcoin
Largest marketplace for buying and selling Bitcoin ordinal inscriptions
Questions People Also Ask
- How much does it cost to inscribe?
- Depends on file size and current Bitcoin fee rates. Formula: file_size_bytes x fee_rate_sats_per_vByte / 4 (witness discount). A 100KB image at 10 sat/vB: approximately 250,000 sats (~$150 at $60K BTC). At 50 sat/vB: ~$750. Wait for low-fee periods (weekends, off-peak hours) to inscribe cheaply. Services like OrdinalsBot show real-time fee estimates.
- Can ordinal inscriptions be deleted?
- No. Once inscribed and confirmed in a Bitcoin block, the data is permanent and immutable. It exists in every full node copy of the blockchain. There is no admin function, no delete button, no way to remove it. This is both the feature (permanence) and the limitation (inscribe carefully, you cannot edit or remove).
- Do I need a special wallet for ordinals?
- You need a wallet that supports Taproot addresses (bc1p...) and ideally has ordinal-awareness (knows which satoshis carry inscriptions so you do not accidentally spend them as fees). Wallets: Xverse, Hiro Wallet, UniSat, and Sparrow (with ordinals plugin). Standard wallets like BlueWallet can receive inscriptions but might accidentally spend the inscribed satoshi in future transactions.