Question 1

Which hash algorithm should I use?

Accepted Answer

Use SHA-256 for anything security-sensitive. MD5 and SHA-1 are fast and fine for non-security checks like cache keys or quick integrity checks, but they are considered broken for cryptographic purposes and should not be used to protect passwords or signatures.

Question 2

Is hashing reversible — can I get the text back?

Accepted Answer

No. Hashing is one-way. You cannot recover the input from a digest; you can only re-hash a candidate input and compare the results.

Question 3

Why do the algorithms produce different lengths?

Accepted Answer

Each algorithm has a fixed output size: MD5 is 128 bits (32 hex characters), SHA-1 is 160 bits (40 characters), SHA-256 is 256 bits (64 characters), SHA-384 is 384 bits (96 characters), and SHA-512 is 512 bits (128 characters).

Question 4

Can I hash passwords with this?

Accepted Answer

A plain hash is not appropriate for storing passwords. Use a dedicated password hashing algorithm such as bcrypt, scrypt, or Argon2 with a per-user salt instead.

Question 5

Is my text sent to a server?

Accepted Answer

No. All hashing runs locally in your browser, so your input never leaves your device.

Hash text with MD5, SHA-1, SHA-256, SHA-384 & SHA-512