MD5 vs SHA-256: Which Hash Should You Use?

A hash function takes input of any size — a word, a file, a database — and produces a fixed-length output called a digest. The same input always yields the same digest, and even a one-character change scrambles the result completely. Good hashes are also one-way: you can't reverse the digest back into the original.

MD5 (Message Digest 5) dates to 1991 and produces a 128-bit digest, shown as 32 hex characters. SHA-256 is part of the SHA-2 family published by NIST and produces a 256-bit digest, shown as 64 hex characters. That longer output isn't just cosmetic — it's part of why SHA-256 is far harder to attack.

On raw speed, MD5 wins. It's lighter and faster to compute, which is exactly why it lingered in so many systems. SHA-256 does more work per input, so it's a bit slower — though on modern hardware the difference is negligible for everyday use.

Security is where they diverge sharply. MD5 is broken: researchers demonstrated practical collisions back in 2004, forged SSL certificates using MD5 collisions in 2008, and today tools can generate a colliding pair on a laptop in under a minute. A collision means two different inputs produce the identical digest — catastrophic if you're relying on the hash to prove a file hasn't been tampered with. SHA-256, by contrast, has no known practical collision or preimage attack. It underpins TLS certificates, Bitcoin, code signing, and Git's newer object model. For anything involving trust, SHA-256 is the answer.

MD5 isn't useless — it's just not a security tool anymore. As a fast, non-cryptographic checksum it's perfectly reasonable: deduplicating files on a trusted machine, generating cache keys, or sanity-checking that a copy completed without corruption from random errors. In those cases you're guarding against accidents, not attackers.

Where MD5 must never appear: password storage, digital signatures, certificate validation, or verifying downloads against a malicious party. If an adversary could benefit from forging a match, MD5 gives them the door. And a reminder that catches a lot of people — passwords shouldn't be protected with any plain hash, MD5 or SHA-256. Use a purpose-built password hash like bcrypt, scrypt, or Argon2, which are deliberately slow to resist brute-force cracking.

Tooldrop's Hash Generator at /dev/hash-generator computes SHA-1, SHA-256, SHA-384, and SHA-512 digests using your browser's built-in Web Crypto API. You'll notice MD5 isn't on the list — that's intentional. Web Crypto doesn't implement MD5, and given how broken it is, steering toward SHA-256 is the right default anyway.

Because the hashing runs entirely on your device, your text never leaves your machine — nothing is uploaded to a server. It's free, there's no sign-up, and there are no limits on how much you hash. Paste your text, pick SHA-256, and the digest appears instantly, ready to copy. Like most tools on Tooldrop, it works in-browser so your data stays private.