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SHA-256 vs SHA-512: What’s the Difference?

Last updated: 23 July 2026

SHA-256 and SHA-512 are both members of the SHA-2 family of cryptographic hash functions, designed by the NSA and published by NIST. Both are secure and widely used. The main differences are the size of the output and the internal word size — which, perhaps surprisingly, affects speed depending on your hardware.

Output size

The number in the name is the digest length in bits:

• SHA-256 produces a 256-bit hash — 64 hexadecimal characters.
• SHA-512 produces a 512-bit hash — 128 hexadecimal characters.

A longer hash has a larger space of possible values, which raises the theoretical bar against collisions. In practice both are far beyond any feasible brute-force attack today.

Speed

SHA-512 works on 64-bit words, while SHA-256 works on 32-bit words. On modern 64-bit CPUs, SHA-512 can actually be faster than SHA-256 for large inputs, because it processes more data per operation. On 32-bit or constrained hardware, SHA-256 is usually faster and uses less memory.

Security

Both are considered secure with no practical collision attacks. SHA-512 has a larger internal state, which gives it a bigger margin and makes it more resistant to certain theoretical attacks (and to length-extension in some variants like SHA-512/256). For most applications, SHA-256 is more than strong enough.

When to use each

• SHA-256: the default choice — TLS certificates, blockchain, file checksums, most APIs. Widely supported and compact.
• SHA-512: when you want extra margin, are hashing large data on 64-bit servers, or a spec requires it.

Important: hashing is not encryption

A hash is one-way — you cannot “decrypt” it back to the original. That is exactly why hashes are used for checksums and (with a salt and a slow algorithm like bcrypt/Argon2) for password storage. Never use a plain SHA hash on its own to store passwords.

Generate a hash for free

You can compute SHA-1, SHA-256, SHA-384 or SHA-512 of any text right in your browser with our Hash Generator — it uses the browser’s built-in crypto and never uploads your input.

Quick answer

Use SHA-256 by default. Reach for SHA-512 when you want a longer digest, extra security margin, or better performance on 64-bit servers.