SHA-256 Hash Generator — Generate SHA256 Hashes Online
FreeGenerate SHA-256 hashes from text or files instantly. 64-character hex output. Used for data integrity, API signing, and certificate fingerprints. Free, browser-based.
What's next
Settings guide
Output format:
- ·Hex (lowercase) — 64 lowercase hexadecimal characters. Standard for most tools, APIs, and documentation.
- ·Hex (uppercase) — 64 uppercase characters. Used by some Windows tools and certain enterprise APIs.
- ·Base64 — The 256-bit hash encoded as Base64. Produces a 44-character string. Used in HTTP
Digestheaders, JWK thumbprints, and some API signing schemes.
Input type:
- ·Text (UTF-8) — Hashes the UTF-8 encoded bytes of the input string.
- ·File — Hashes the complete binary file content, byte for byte.
Format comparison
SHA-256 vs SHA-512: Both are secure. SHA-512 produces a 512-bit (128-character) hash and is slightly faster on 64-bit systems for large inputs due to how it processes blocks. SHA-256 is the standard choice for most applications — it is what TLS certificates, Bitcoin, and most modern API signing schemes use.
SHA-256 vs MD5 for file checksums: SHA-256 is preferred for security-sensitive integrity checks. MD5 is still used for simple download verification on low-risk files where collision attacks are not a realistic threat. For any security context — code signing, certificate fingerprinting, API authentication — SHA-256 is the minimum standard.
How it works
Pad and prepare
The input bytes are padded to a multiple of 512 bits. The padding starts with a 1-bit, followed by zeros, then the original input length encoded in the final 64 bits.
Initialise constants
Eight 32-bit hash values are initialised from the fractional parts of the square roots of the first 8 prime numbers. These are the algorithm's starting state.
Compress 512-bit blocks
Each 512-bit block goes through 64 rounds of mixing using bitwise operations, addition, and 64 round constants (derived from cube roots of primes). Each round updates the running hash state.
Output the digest
The final hash state — eight 32-bit words — is concatenated and written as 64 hexadecimal characters. This is your SHA-256 hash.
About this format
SHA-256 (Secure Hash Algorithm 256-bit) produces a 256-bit hash represented as a 64-character hexadecimal string. It is the current standard for data integrity verification, digital signatures, certificate fingerprinting, and HMAC-based API request signing.
Where MD5 has collision vulnerabilities, SHA-256 has none that are computationally feasible. A single bit change in the input produces a completely different output — a property called the avalanche effect. This makes SHA-256 the right choice when the integrity of the hash matters for security, not just error detection.
Paste text or upload a file — the SHA-256 hash is computed immediately, entirely in your browser.