What a discriminator is
Anchor tags every instruction, account, and event with the first 8 bytes of a SHA-256 hash. The program reads those bytes first to know which handler or type it is looking at.
Free tool
Anchor discriminator calculator
This Anchor discriminator calculator turns an instruction, account, or event name into its 8-byte tag. You get hex, a byte array, base58, and a Rust literal, with the exact string that was hashed.
No sign-up. Runs in your browser. Last reviewed by the Builderz team.
Everything runs in your browser. Nothing is sent anywhere.
Type a name to see its discriminators.
Batch
How it works
Three namespaces
An instruction hashes "global:" plus the snake_case name, for example global:initialize. An account hashes "account:" plus the PascalCase type name. An event hashes "event:" plus the PascalCase type name. The same word gives three different values.
Name normalisation
Anchor hashes the instruction name in snake_case and the account or event type name as written in Rust, which is PascalCase by convention. This tool normalises what you type the same way and shows the preimage, so transferTokens becomes global:transfer_tokens and vault_state becomes account:VaultState. If your Rust name breaks the convention, type it exactly.
Where the 8 bytes sit
In instruction data they are bytes 0 to 7, followed by the Borsh-encoded arguments. In an account they are the first 8 bytes of the account data, followed by the fields. Anchor 0.30 and later IDLs carry the values inline, so older IDLs and raw logs are where you need to compute them.
Nothing leaves the page
The hash runs in your browser with the Web Crypto API. Names are not sent to a server.
Where the numbers come from
More free tools
- Solana cost calculator
- Interactive Solana launch checklist
- Solana pre-audit readiness score
- Anchor IDL inspector and PDA finder
- Solana rent calculator
- Solana priority fee calculator
- Solana address checker
- Lamports to SOL converter
- Solana epoch countdown
- AI agent cost calculator
- MCP server inspector
- AI agent production readiness score
- llms.txt checker and generator
Questions about this tool
Why does my program use a different value for an account?
Newer Anchor versions let you set a custom discriminator with #[account(discriminator = ...)] or on an instruction. When you do, the default hash is not used. Read the value from the IDL or the source instead of computing it.
Is the discriminator a security check?
No. It is a type tag, anyone can compute it, and it only tells the program which layout to expect. Owner checks, signer checks, and seed checks still decide who is allowed to do what.
What about Shank or native programs?
Native programs and Shank-based programs have no shared discriminator convention. Each one picks its own tag, often a single byte. This tool only covers the Anchor rule.
How do event discriminators work?
An event hashes "event:" plus the PascalCase name. Anchor writes those 8 bytes at the start of the event data in the program log or the self-CPI instruction, so an indexer can tell event types apart.
Beyond the tool
Need this done for your program? Start with production build.
$10K-$40K. Book an intro call, or send a brief with what the tool showed you. We reply within one business day.
Acceptance in writing
Criteria agreed before build starts
Proposal in 48h
After a qualified scoping call
Change control
Scope, exclusions, and owners named