Argon2 Hash Generator
Free online Argon2 hash generator and verifier. Choose argon2id, argon2i or argon2d with custom time, memory and parallelism. Runs in a Web Worker via WebAssembly — 100% local, nothing is uploaded.
What is Argon2 and why should I use it?
Argon2 is the winner of the Password Hashing Competition and the modern standard for password hashing. Unlike SHA-256, it is deliberately slow and memory-hungry, making large-scale brute-force attacks extremely expensive.
Which Argon2 variant should I choose?
Argon2id is the recommended default: it combines the side-channel resistance of Argon2i with the GPU-resistance of Argon2d. Choose argon2i for older setups that require it and argon2d only for compatibility.
What do the time, memory and parallelism parameters mean?
Time cost is the number of iterations, memory is the RAM used in kilobytes, and parallelism is the number of independent lanes. OWASP recommends a minimum of 19 MiB memory, 2 iterations and 1 lane — raising memory is generally safer than raising iterations.
What is the encoded output format?
The encoded string follows the PHC format, for example $argon2id$v=19$m=65536,t=3,p=4$<salt>$<hash>. It embeds every parameter and the salt, so you can verify passwords later without storing anything else.
Can I verify an existing Argon2 hash?
Yes. Switch to the verify tab, paste the full encoded hash and enter the password to check. The tool re-derives the hash locally and tells you whether it matches.
Are my passwords sent anywhere?
No. Hashing runs in a local Web Worker using the Argon2 WebAssembly build. Your password never leaves the browser and nothing is logged.
Is a custom salt safe to use?
The salt does not need to be secret — it only needs to be unique per password. The built-in random salt generator produces 16 random bytes, which is the recommended choice unless you have a specific reason to reuse a salt.
Why does hashing take a moment to start?
On first use the Argon2 WebAssembly engine (about 26 KB) is loaded into the worker. After that, the runtime cost comes from the parameters themselves: high memory settings are intentionally slow.
How to Use Argon2 Hash Generator
Argon2 Hash Generator creates and verifies Argon2 password hashes entirely in your browser. The hashing runs in a Web Worker using the Argon2 WebAssembly build — your password never leaves the device and nothing is uploaded or logged.
- Open the Generate hash tab, type the password in the Password field and pick a variant: Argon2id is the recommended default, with Argon2i and Argon2d for compatibility cases.
- Tune the cost parameters: Iterations (time cost), Memory in KB and Parallelism (lanes). OWASP suggests at least 19 MiB of memory and 2 iterations; higher memory is usually better than more iterations.
- Keep Random salt (16 random bytes per hash) or switch to Custom salt and type your own text. Set the hash length in bytes if your backend expects something other than 32.
- Press Generate hash. The result shows the full PHC-encoded string (safe to store in your database) plus the raw hex digest, along with the computation time.
- To check a password later, open the Verify hash tab, paste the encoded string and enter the password — the verdict shows MATCH or NO MATCH.
Store the whole encoded string (not just the hex digest) — it contains the variant and all cost parameters, so future verification and parameter upgrades keep working.
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