About the SHA-256 Hash Generator
What is a SHA-256 hash?
SHA-256 is the workhorse of modern cryptography. It produces a 256-bit fingerprint, written as 64 hexadecimal characters, and is part of the SHA-2 family designed by the NSA and standardized by NIST. It secures TLS certificates, software signatures, blockchains and countless other systems.
Unlike MD5 and SHA-1, SHA-256 has no known practical weaknesses and is the recommended default when you need a general-purpose cryptographic hash. (Note that raw SHA-256 is still not the right tool for storing passwords, because it is designed to be fast; a dedicated password hash like bcrypt or Argon2 is what you want there.) This tool uses your browser's native Web Crypto implementation, so it is both fast and completely private, nothing is uploaded.
How to Use This Tool
- Enter your input. Type or paste text on the Text tab, or switch to the File tab and drop in a file. The SHA-256 hash appears instantly.
- Choose the output. Switch between hexadecimal and Base64, and pick upper or lowercase hex.
- Verify a checksum. Paste a hash you were given into the compare box and the tool tells you instantly whether it matches.
- Copy the result. One click copies the SHA-256 hash to your clipboard.
Common Use Cases
- File and download integrity: the modern standard for checksums; compare against the SHA-256 a project publishes.
- Digital signatures and certificates: SHA-256 underpins most current TLS certificates and code signing.
- Blockchain and Bitcoin: Bitcoin addresses and proof-of-work are built on SHA-256.
- API request signing: HMAC-SHA256 authenticates requests for AWS, webhooks and many other services; enable HMAC mode and add the key.
Frequently Asked Questions
Is SHA-256 secure?
Yes. SHA-256 has no known practical collision or preimage attacks and is the recommended general-purpose cryptographic hash today. It is trusted for TLS certificates, software signing and blockchains. The one job it is not suited for is storing passwords, where a deliberately slow hash like bcrypt or Argon2 is correct.
How long is a SHA-256 hash?
SHA-256 is 256 bits, shown as 64 hexadecimal characters or 44 characters in Base64. The length is fixed no matter how large the input.
Can SHA-256 be reversed or decrypted?
No. A hash is a one-way function, so there is no way to compute the original input from the hash. The only way to find an input that produces a given SHA-256 is to guess, which is infeasible for anything with real entropy. That is precisely why hashes are useful.
What is the difference between SHA-256 and SHA-2?
SHA-2 is the family; SHA-256 is its most common member. The family also includes SHA-224, SHA-384 and SHA-512, which differ mainly in output length. When people say "SHA-2" they usually mean SHA-256.
What is HMAC-SHA256?
HMAC-SHA256 is SHA-256 combined with a secret key to create a keyed hash used for authentication, for example signing API requests or verifying webhooks. Turn on HMAC mode above and enter your secret key.
Can I hash a file with SHA-256?
Yes. Switch to the File tab and drop in any file. It is read and hashed entirely in your browser and matches what sha256sum or certutil would output.