Are files uploaded to a server?
No. The input file bytes are processed inside your browser. Some tools download their JavaScript libraries from public CDNs, but the files themselves are not uploaded.
SHA-256 file checksum checker
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About this tool
SHA-256 file checksum checker without uploading
Choose a file, calculate a SHA-256, SHA-384, SHA-512 or legacy SHA-1 checksum, and optionally compare the result with a published expected value.
Before you start
Matching a trusted checksum helps confirm file integrity, but a hash from an untrusted source cannot establish file safety.
Do I need an account or a paid plan?
No. The current version is free, has no registration and runs on devices with a compatible modern browser.
Can a SHA-256 checksum prove a download is authentic?
Matching a checksum confirms the file matches the expected bytes, provided the expected checksum comes from a source you trust. A hash alone does not prove who published it.
A checksum answers “did these bytes change?” — not “is this file safe?”
Cryptographic hashes turn file bytes into a fixed-length fingerprint. If a publisher gives you a trusted SHA-256 value, calculating the hash of your download lets you check whether your copy matches the bytes the publisher intended. Even a one-bit change produces a very different hash.
A matching checksum does not prove that the publisher is trustworthy or that the file is free of malware; it proves only that your file matches the referenced bytes. The expected hash must come from a source you trust, ideally a channel independent from the download itself when integrity is important.
Practical checks
- Prefer SHA-256 or a stronger modern hash for integrity checks.
- Copy the expected checksum from a trusted publisher source.
- Use antivirus or other security checks separately when file safety is the concern.
Practical walkthrough · hash checker
Verify a download before sharing it
Example task: A software publisher gives you an official SHA-256 checksum for a release ZIP.
Try this workflow
- Select the downloaded ZIP in the hash checker.
- Compare the entire calculated hexadecimal checksum with the value supplied from the publisher’s trusted channel.
- If any character differs, treat the files as different and investigate before using the archive.
What to expect
Identical SHA-256 results are strong evidence that the compared bytes match, assuming the expected checksum is authentic.
When to take extra care
A matching hash alone does not prove the software is harmless; an attacker can publish a malicious file and its matching hash together.