Ithy

SHA-256 generator for exact UTF-8 text

Generate a SHA-256 checksum of the exact text in the field. UTF-8 encoding happens before hashing. Optionally compare the result with a 64-digit hexadecimal digest from a trusted source.

Free to use, with no sign-in. Inputs and results stay in this page and are not sent with the form. Download a result before leaving; this tool does not save your work.

Enter text or data

Worked result

SHA-256(abc) = ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad.

  1. Encode abc as the bytes 61 62 63 in hexadecimal.
  2. Calculate SHA-256 with the browser cryptography API.
  3. Represent the 32-byte digest as 64 hexadecimal digits.

Check the standard abc digest

This example contains the three ASCII letters a, b and c, with no trailing newline, space or byte-order mark.

UTF-8 text: abc
Bytes: 3
SHA-256:
ba7816bf8f01cfea414140de5dae2223
b00361a396177a9cb410ff61f20015ad
(The digest is one continuous 64-digit hexadecimal string.)

Adding a newline changes the input bytes and therefore the checksum. This text tool hashes UTF-8 text, not the original bytes of a file you might have copied from.

A checksum identifies bytes, not trust

SHA-256 produces a fixed 256-bit digest. The hexadecimal representation has two characters per byte, hence 64 digits. Comparison ignores hex letter case but requires all 64 digits.

A digest comparison is meaningful only if the expected digest comes from an appropriately trusted channel. An attacker able to replace both data and its displayed digest can make them agree. This tool does not add a key, prove an author’s identity or verify a digital signature.

text → UTF-8 bytes → SHA-256 → 32 bytes
32 digest bytes × 2 hex digits per byte = 64 hex digits

Input limits and common mistakes

The input limit is 200,000 UTF-16 units. The browser must support Web Crypto in a secure context. Invalid unpaired surrogate input is rejected. Empty text is allowed and has its own well-defined digest.

Text line endings, invisible characters and Unicode normalization affect bytes. The tool performs no normalization. It is not a password-storage system, file-signature verifier or encryption service. For a file checksum, hash the original file bytes with an appropriate local tool.

Questions about sha-256 text checksum

Why is my result different after pasting text?

A newline, space, different Unicode normalization or other invisible character can change the byte sequence. Inspect the exact input and byte count.

Can SHA-256 be decoded to recover text?

It is a hash rather than reversible encoding. Guessable inputs can still be tested, which is why an ordinary hash is not suitable password storage.

Does a matching checksum prove a download is authentic?

Only if the expected checksum is obtained from a trusted source and the actual original file bytes are hashed. This tool hashes text.

Sources and verification

These references explain the formulas or formats. The worked examples above were created for this tool and checked against independent calculations or format round trips. AI-assisted development does not imply a named human expert review.

Published 2026-10-23. Examples are illustrations, not measurements of a service or claims about search rankings.

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