Is my input sent to a server?

No. Hashing happens in your browser through the native Web Crypto API, with no network request. This is worth knowing because online hash tools that do send your input are an obvious way to leak whatever you were hashing.

Can a hash be reversed?

Not directly, because hashing discards information. But short or predictable inputs can be recovered by simply hashing every candidate and comparing, which is what rainbow tables and cracking rigs do. A hash of a common password offers essentially no protection.

Should I still use MD5 or SHA-1?

Only as a non-security checksum, for example a cache key or a quick change detector. Both have practical collision attacks, so an attacker can craft two different inputs that hash identically. Never use them for signatures, certificates, or integrity verification against a motivated adversary.

Can I use this to hash passwords for my database?

No. General-purpose hashes are designed to be fast, which makes them a poor fit for password storage since an attacker can try billions of guesses per second. Use a purpose-built password hash such as bcrypt, scrypt or Argon2, with a unique salt per user.

Why does an empty input still produce a hash?

Because the empty string is a valid input with a valid digest. The well-known SHA-256 value beginning e3b0c442 is the hash of zero bytes, and seeing it is a useful hint that whatever you meant to hash was actually empty.

Generators

Hash Generator — MD5, SHA-1, SHA-256

Hash text with MD5, SHA-1, SHA-256, SHA-384 or SHA-512.

Input

0 bytes

Text to hash

MD5128 bitNot for security

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Broken — practical collisions since 2004. Checksums only.

SHA-1160 bitNot for security

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Broken — collisions demonstrated in 2017. Checksums only.

SHA-256256 bitSecure

—

The current default for general-purpose hashing.

SHA-384384 bitSecure

—

Truncated SHA-512.

SHA-512512 bitSecure

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Often faster than SHA-256 on 64-bit hardware.

Hashing passwords for storage? None of these are suitable — they are designed to be fast, which is exactly what an attacker with a stolen database wants. Use bcrypt, scrypt or Argon2 with a unique salt per user.

About this tool

A hash function reduces any input to a fixed-length fingerprint. The same input always produces the same output, a different input almost certainly produces a different output, and you cannot work backwards from the fingerprint to the original. That makes hashes useful for comparing things without storing them, and for detecting whether data changed.

The everyday uses are verifying that a downloaded file matches its published checksum, generating a cache key or an ETag from content, checking whether two blobs of text are identical without diffing them, and computing the digest that a webhook signature or API request signature is built on.

Which algorithm to use depends entirely on whether an attacker is involved. MD5 and SHA-1 are both cryptographically broken: it is practical to construct two different inputs with the same hash, which has been demonstrated with real certificates and real documents. They are fine as non-adversarial checksums and you will keep meeting them in older systems, but they must not be used for signatures, integrity guarantees, or anything security-relevant. Use SHA-256 or better for that.

The SHA family here is computed with the Web Crypto API built into your browser, which is both faster and better audited than any bundled JavaScript implementation. MD5 is not offered by Web Crypto, precisely because it is broken, so it is computed by a small implementation included on this page.

One thing hashes are not is a way to store passwords. A raw SHA-256 of a password is far too fast to compute, which is exactly what an attacker with a stolen database wants. Password storage needs a deliberately slow, salted function such as bcrypt, scrypt or Argon2.

How to use it

Type or paste your text into the input panel.
Read the digest for every algorithm at once.
Copy whichever hash you need.

Frequently asked questions

Is my input sent to a server?: No. Hashing happens in your browser through the native Web Crypto API, with no network request. This is worth knowing because online hash tools that do send your input are an obvious way to leak whatever you were hashing.
Can a hash be reversed?: Not directly, because hashing discards information. But short or predictable inputs can be recovered by simply hashing every candidate and comparing, which is what rainbow tables and cracking rigs do. A hash of a common password offers essentially no protection.
Should I still use MD5 or SHA-1?: Only as a non-security checksum, for example a cache key or a quick change detector. Both have practical collision attacks, so an attacker can craft two different inputs that hash identically. Never use them for signatures, certificates, or integrity verification against a motivated adversary.
Can I use this to hash passwords for my database?: No. General-purpose hashes are designed to be fast, which makes them a poor fit for password storage since an attacker can try billions of guesses per second. Use a purpose-built password hash such as bcrypt, scrypt or Argon2, with a unique salt per user.
Why does an empty input still produce a hash?: Because the empty string is a valid input with a valid digest. The well-known SHA-256 value beginning e3b0c442 is the hash of zero bytes, and seeing it is a useful hint that whatever you meant to hash was actually empty.