MD5 Hash Generator Online Free

How to generate a hash

Type or paste text, pick an algorithm, and the hash appears instantly. The same input always produces the same output, and the smallest change to the input produces a completely different result.

What a hash is for

A hash is a fixed-length fingerprint of some data. It is one-way by design: you cannot work backwards from the hash to the original. That makes it useful for checking that something has not changed. Compare the hash of a downloaded file against the one the publisher listed, and a mismatch means the file is corrupt or tampered with.

Choosing between the algorithms

MD5 is fast, ubiquitous and cryptographically broken. Practical collision attacks, where two different inputs produce the same hash, have existed since 2004. It is still perfectly reasonable as a checksum against accidental corruption, and completely unsuitable for anything security-related.

SHA-1 is also broken, demonstrated in practice in 2017, and has been removed from browsers and certificate authorities. Treat it as legacy: use it to verify against old systems that still emit it, not to protect anything new.

SHA-256 remains sound and is the sensible default for integrity checking today. It underpins TLS certificates, Git object naming and Bitcoin.

An important warning about passwords

None of these should be used to store passwords. Fast hashes are exactly what an attacker with a stolen database wants, because speed lets them try billions of guesses. Password storage needs a deliberately slow, salted algorithm such as bcrypt, scrypt or Argon2, not MD5 or SHA.

Frequently asked questions

Can a hash be reversed?

Not mathematically. But short or common inputs can be looked up in precomputed tables, which is effectively the same thing for anything guessable.

Why is the length always the same?

By design. MD5 is always 32 hex characters, SHA-256 always 64, no matter how much text you feed in.

Is my text sent anywhere?

No. Hashing runs entirely in your browser.