SuperCalc

UUID & Hash Generator

Generate UUID v4 identifiers and compute SHA-256, SHA-1, SHA-384, and SHA-512 hashes. Everything runs in your browser using the Web Crypto API.

UUID & Hash Generator

Generate UUIDs and compute cryptographic hashes.

53549449-72be-4bdc-ba6a-0aaa2497e653

UUID v4 (random). Generated with crypto.randomUUID().

How it works

UUID v4 uses crypto.randomUUID() to generate 128-bit random identifiers in the standard 8-4-4-4-12 hex format. The "4" in the third group indicates version 4 (random).

Cryptographic hashes use the SubtleCrypto.digest() API to compute one-way hash functions. The same input always produces the same hash, but you cannot reverse a hash to recover the original input.

SHA-256 produces a 256-bit (64 hex character) output. SHA-512 produces 512 bits (128 hex characters). These are the same algorithms used in TLS, Bitcoin, and digital signatures.

FAQ

What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier that is practically unique across all systems. Version 4 UUIDs are randomly generated, with about 5.3 x 10^36 possible values — making collisions statistically impossible.
When should I use a UUID vs an auto-increment ID?
Use UUIDs when you need IDs that are unique across distributed systems without a central authority, when IDs need to be generated client-side, or when you don't want sequential IDs to be guessable. Use auto-increment when storage efficiency matters or you need simple ordering.
What hash algorithm should I use?
SHA-256 is the default choice for most purposes — it's secure, widely supported, and fast. SHA-1 is deprecated for security but still used in some legacy systems. SHA-384 and SHA-512 offer longer outputs for extra security margins.
Is this tool secure?
Yes. UUIDs are generated using crypto.randomUUID() and hashes are computed via the Web Crypto API (SubtleCrypto.digest). Both run entirely in your browser — no data is ever sent to a server.
Can I generate UUIDs in bulk?
Yes. Set the count (up to 50) and click Generate. All UUIDs are generated instantly and can be copied individually or all at once.

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