Hash Generator
How it works
Type or paste text and seven hashes are computed at once, in real time: MD5, SHA-1, SHA-256, SHA-384, SHA-512, SHA-3 (256) and BLAKE2b. Switch to File mode to hash any file by dragging it onto the drop zone. SHA-1, SHA-256, SHA-384 and SHA-512 run on the browser's built-in Web Crypto API (window.crypto.subtle.digest); MD5 uses a small pure-JavaScript implementation; SHA-3 (Keccak) uses js-sha3 and BLAKE2b uses blakejs. Everything runs locally, so no network request is made.
A cryptographic hash takes an input of any length and produces a fixed-length fingerprint. SHA-256 always returns exactly 256 bits (64 hex characters), SHA-512 returns 512 bits (128 hex chars), SHA-3-256 is 256 bits, BLAKE2b defaults to 512 bits. Any single-bit change in the input, flipping one character or adding a newline at the end, produces a completely different hash. That property is what makes hashes useful for verifying integrity: download an installer, compute its SHA-256, compare against the value the vendor published. If they match, you got the file the vendor intended.
Not every hash is equal. MD5 and SHA-1 are considered broken for security purposes: researchers have demonstrated practical collisions (two different inputs that produce the same hash). They are still fine for non-adversarial checksumming where you only care about accidental corruption, which is why git uses SHA-1 and many CDN ETags still use MD5, but do not use them to sign data, verify file authenticity from an untrusted source, or derive keys. SHA-256, SHA-384, SHA-512, SHA-3 and BLAKE2b have no known practical collision attacks and are what modern systems rely on.
The newer algorithms matter for specific situations. SHA-3 (Keccak) was selected in 2015 by NIST as an alternative to SHA-2 built on a completely different internal construction (sponge vs Merkle–Damgård), so a theoretical break of SHA-2 would not automatically break SHA-3. BLAKE2b is significantly faster than SHA-2 and SHA-3 on modern CPUs, which is why Argon2, WireGuard, Zcash and IPFS use it internally, and it is the right choice when you want post-SHA-2 security with better throughput.
Hashes are one-way. You cannot invert a hash to recover the input. What attackers do instead is pre-compute hashes of common passwords (rainbow tables) and look the hash up. That is why real password storage uses a slow, salted hash like bcrypt, scrypt or Argon2 rather than a bare SHA-256.
Frequently Asked Questions
Which hash algorithms does the tool compute?
- Seven, all at once: MD5, SHA-1, SHA-256, SHA-384, SHA-512, SHA-3 (256-bit output, also known as Keccak-256) and BLAKE2b (512-bit output). Paste text or drop a file and every hash updates in parallel.
Is my data uploaded to a server?
- No. The SHA-1/256/384/512 hashes use the browser's built-in Web Crypto API (crypto.subtle.digest), MD5 uses a small pure-JS implementation bundled with the page, and SHA-3 and BLAKE2b use the js-sha3 and blakejs libraries. All of that code runs in your browser tab, and DevTools → Network confirms zero outbound requests when you hash.
Can I hash large files?
- Yes. File mode reads the file through the File API and feeds it to each hasher without loading it into a string. Files up to several gigabytes work on a modern laptop; the practical limit is the browser's free memory and how long you're willing to wait.
Why is MD5 included if it's not secure?
- Because MD5 is still in everyday use for non-security tasks: content-addressed caches, CDN ETag generation, basic file-integrity checks where you only care about accidental corruption, and interop with legacy systems. It is also the fastest of the seven, which matters when you are hashing a lot of data. For anything security-sensitive, use SHA-256, SHA-512 or SHA-3 instead.
What is the difference between SHA-1, SHA-2 and SHA-3?
- SHA-1 is the first-generation Secure Hash Algorithm (160-bit, broken since 2017's SHAttered). SHA-2 is the current mainstream family: SHA-224, SHA-256, SHA-384 and SHA-512 are all SHA-2 variants and remain secure. SHA-3 is a completely different design (Keccak sponge construction) chosen by NIST in 2015 as an algorithmically-independent backup in case SHA-2 is ever broken. SHA-3 is slower than SHA-2 in software, but resistant to the length-extension attacks that affect SHA-2.
When should I use BLAKE2b?
- When you want modern security with better performance than SHA-2 or SHA-3 on typical hardware. BLAKE2b was designed after SHA-3 by the same team and targets pure speed, which is why Argon2 (password hashing), WireGuard (VPN), Zcash (cryptocurrency) and IPFS use it internally. For a new application with no specific interop requirement, BLAKE2b is often the right pick; for interop with existing systems (TLS certificates, HTTPS, JWT), stick with SHA-256.
Can I use these hashes for passwords?
- No. A bare SHA-256, SHA-3 or BLAKE2b is far too fast: a GPU can try billions of candidate passwords per second against any of them. Store passwords with a purpose-built slow hash like bcrypt, scrypt or Argon2id, always with a unique per-user salt.
Why is my SHA-256 of an empty string e3b0c442…?
- Because that is the defined SHA-256 output for the empty string. Every hash algorithm has one (SHA-3-256 of empty is a6b…, BLAKE2b is 786a…). Seeing these values unexpectedly in production means your code hashed a null or empty input, usually a sign that something upstream was not reading the real content.
Hash algorithm comparison
Output size, security status and typical uses for every algorithm this tool computes. Knowing the expected output length is useful when validating hashes from third-party sources.
| Algorithm | Output bits | Hex characters | Status | Typical use |
|---|---|---|---|---|
| MD5 | 128 | 32 | Broken (collisions since 2004) | Checksums, ETags, cache keys (never for security) |
| SHA-1 | 160 | 40 | Broken (SHAttered, 2017) | Git object IDs, legacy TLS (avoid for new systems) |
| SHA-256 | 256 | 64 | Secure | TLS certificates, Bitcoin, file integrity, JWT signatures |
| SHA-384 | 384 | 96 | Secure | TLS 1.3 AEAD, some government standards, Apple APNs |
| SHA-512 | 512 | 128 | Secure | Performance-optimal on 64-bit CPUs; same security level as SHA-256 |
| SHA-3 (256) | 256 | 64 | Secure | Keccak sponge construction; NIST backup to SHA-2, resistant to length-extension attacks |
| BLAKE2b | 512 (default) | 128 | Secure | Faster than SHA-256 on modern CPUs; used by Argon2, WireGuard, Zcash, IPFS |
For password storage use a purpose-built slow hash (bcrypt, scrypt, Argon2id), never a bare cryptographic hash from this table. For integrity checks on untrusted input use SHA-256, SHA-512, SHA-3 or BLAKE2b; MD5 and SHA-1 are only safe for non-adversarial checksumming.