What is hashing?
Hashing transforms input data into a fixed-length string using a one-way mathematical function. Common algorithms include MD5 (128-bit, legacy), SHA-1 (160-bit, deprecated for security), SHA-256 (256-bit, widely used), and SHA-512 (512-bit, maximum security). This tool uses the browser's native SubtleCrypto API for generation.
What a hash function does
A hash function turns any input — a word, a file, a password — into a fixed-length string of characters called a digest. The same input always produces the same digest, but the process is one-way: you cannot reverse a digest back into the original input. Hashes are used to verify data integrity, index content, and store password verifiers safely.
Even a tiny change to the input produces a completely different digest, which is what makes hashing useful for detecting whether a file or message has been altered.
Choosing an algorithm
SHA-256 and SHA-512 are modern, secure choices for integrity checks and digital fingerprints. MD5 and SHA-1 are fast but cryptographically broken — attackers can craft collisions — so they should only be used for non-security checksums, never for passwords or signatures. For storing passwords specifically, a dedicated password hash such as bcrypt or Argon2 is required rather than a plain SHA hash.
Salting and why it matters
Hashing the same input always gives the same digest, so identical passwords produce identical hashes and can be attacked with precomputed tables. A salt — a unique random value added before hashing — defeats this by making every stored hash different. Dedicated password hashes like bcrypt and Argon2 handle salting for you.
How to generate a hash
- 1Enter your text. Type or paste the text you want to hash.
- 2Choose algorithms. Select MD5, SHA-1, SHA-256, or SHA-512 as needed.
- 3Click Hash and copy. The digest is computed instantly — copy it for your checksum or fingerprint.
Examples
SHA-256 of a word
Input
hello
Output
2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824
MD5 of a word
Fast, but not secure — checksums only.
Input
hello
Output
5d41402abc4b2a76b9719d911017c592
Hash algorithms
Digest length and recommended use.
| Algorithm | Length / use |
|---|---|
| MD5 | 128-bit — legacy checksums only |
| SHA-1 | 160-bit — deprecated for security |
| SHA-256 | 256-bit — secure integrity and fingerprints |
| SHA-512 | 512-bit — secure, larger digest |
Frequently asked questions
Can a hash be reversed?+
No. Hashing is one-way. A digest cannot be turned back into the original input; you can only hash a candidate input and compare digests.
Why is MD5 considered insecure?+
Attackers can create two different inputs with the same MD5 digest (a collision). That makes it unsafe for signatures or security, though it is still fine as a fast non-security checksum.
Should I hash passwords with SHA-256?+
No. Passwords need a slow, salted password hash like bcrypt or Argon2. Plain SHA hashes are too fast and are vulnerable to brute-force attacks.
What is a hash used for?+
Verifying that a file or message has not changed, fingerprinting content, deduplicating data, and building data structures like hash tables.
Is my input sent to a server?+
No. Hashes are computed in your browser, so your text never leaves your device.
Is it free?+
Yes — free with no limits.
What is a checksum?+
A hash used to verify a file downloaded correctly. You hash the file and compare the digest to the one the publisher lists; a match means the bytes are intact.