Checksum Calculator
Free online checksum calculator: choose a file, see its SHA-256, MD5, SHA-1 and CRC-32, and paste the publisher’s checksum to verify your download in the browser.
How to use Checksum Calculator
- 1Press “Hash a file” and choose the download you want to verify.
- 2Paste the checksum from the publisher’s page into “Compare with”.
- 3Read the result: a green match, or a red mismatch that means the file or value differs.
What makes it better
- File-first layout with SHA-256, MD5, SHA-1 and CRC-32 shown together
- Detects the algorithm from the pasted checksum’s length
- Chunked reading with progress, so multi-gigabyte files do not freeze the page
- Nothing is uploaded, so private files stay on your device
- SHA-512, SHA-3 and more under “More algorithms”
About Checksum Calculator
Checksum Calculator is built for one job: proving that the file you downloaded is the file the publisher released. Choose the file, and its SHA-256, MD5, SHA-1 and CRC-32 appear while it is read in chunks on your device, never uploaded. Paste the checksum from the download page and the tool tells you whether it matches and which algorithm it used.
Common uses
- Check an operating system image or installer against the checksum on its download page.
- Confirm a backup or transferred file arrived intact by comparing both ends’ SHA-256.
- Verify a file from a mirror matches the official release before you run it.
- Compare a CRC-32 from a zip listing with the extracted file.
Example
Input
hello world
Result
b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9
Good to know
- A match proves the file equals the one the checksum was made from, but only if you trust where you copied the checksum. Take it from the publisher’s own HTTPS page or a signed file, not from the same untrusted mirror as the download.
- A mismatch means the bytes differ. Common causes are an interrupted or partial download, the wrong file version, or a tampered file, so download again before assuming an attack.
- Prefer SHA-256 when you have a choice. MD5 and SHA-1 can be forged with crafted collisions, and CRC-32 is only an error check, so a match there is weaker evidence.
Checksum Calculator FAQ
How do I verify a download with a checksum?
Hash the downloaded file here, then paste the checksum the publisher lists into “Compare with”. If every character matches, the file is identical to the one that was hashed; any difference means it is not.
What does it mean if the checksums do not match?
The file you hold is not byte-for-byte the file that was hashed. Most often the download was cut short or you have another version, so retry from the official source. A repeated mismatch can mean tampering.
Which checksum should I trust: SHA-256, MD5 or CRC-32?
SHA-256 is the strongest of these and the best choice. MD5 and SHA-1 are fine against random corruption but can be forged on purpose, and CRC-32 only catches accidental bit errors, so treat those as weaker proof.
Does the tool know which algorithm a checksum uses?
It infers it from the length of the value you paste: 8, 32, 40, 56, 64, 96 or 128 hex characters. Where SHA-2 and SHA-3 share a length it tries both, and the message names the algorithm that matched.
Can a checksum tell me a file is safe to open?
No. It only shows the file matches the one that was hashed. If the publisher’s file itself is malicious, the checksum will still match, so verify the source and the checksum’s origin as well.