How to calculate and compare a checksum
- Choose one or more files, or enter the text you want to hash.
- Select the algorithm supplied by the publisher. SHA-256 is a useful default for a new file-integrity check.
- Calculate the checksums. Paste your trusted reference digest to see a match or mismatch for each file.
- Copy a digest or save a JSON checksum report with file names, byte counts and selected hashes.
Checksum calculator, file hash generator: the difference
A checksum is a compact value calculated from data. CRC32 is commonly used to detect accidental corruption. Cryptographic hash functions such as SHA-256 also produce fixed-length digests, with stronger resistance to deliberate collisions.
MD5 and SHA-1 remain useful when matching an existing legacy checksum. They are not suitable for new security-sensitive integrity designs. A plain hash is also not a password-storage scheme or proof that a download came from a particular author.
Same file name does not mean same file
Two files with different names can have the same content and checksum. Two files with the same name can contain different bytes. Compare the digest with a trusted reference, and use the exact same algorithm on both sides.
Formatting JSON changes whitespace, so its file checksum changes even when the values stay the same. Finish in the JSON formatter or CSV viewer before generating a final checksum. Removing PDF metadata also changes the file bytes.
Frequently asked questions
Which hashes and checksums can I calculate?
Calculate SHA-256, SHA-512, SHA-1, MD5 and standard CRC32 (IEEE) for files or UTF-8 text. Select one or several algorithms. CRC32C, CRC16, HMAC and password hashing are not included.
How do I verify a downloaded file?
Obtain the expected checksum from a trusted publisher, select the same algorithm, and calculate the hash of your downloaded file. Paste the hexadecimal checksum into the comparison box. A match means the computed digest matches that reference; it does not by itself prove a file is safe.
Can I hash a large file without uploading it?
Yes. Files are read in 2 MB chunks in a background worker, rather than loaded into memory in full. You can select up to 20 files per batch. Time depends on file size, storage speed, device and selected algorithms. Cancel stops the worker.
Does the hash include the file name or metadata?
File hashing includes every byte inside the file, including embedded metadata. The file name and filesystem timestamps are not part of the hash. Renaming a file alone does not change its checksum; editing its contents does.
Why is my text hash different from another result?
This tool hashes the exact text in the box as UTF-8, without trimming spaces or adding a final newline. Spaces, line breaks and Unicode normalization affect the bytes. Browser text areas normalize line endings to LF. For an exact byte-for-byte check of a saved document, use file mode.