File Checksum Calculator
Check that a downloaded file — an installer, ISO image or backup — is exactly what the publisher released. Drop the file, paste the published checksum and see instantly whether they match.
Runs in your browser
How to use
- Drop or select the file you downloaded.
- Wait a moment while the four checksums are computed in your browser.
- Paste the checksum published by the vendor into the “Expected checksum” box.
- Read the result: “Match” means the file is identical to the one that was published.
How it works
A checksum, also called a hash, is a fixed-length fingerprint calculated from every byte of a file. Change one bit anywhere in the file and the fingerprint changes completely, which is why vendors publish it next to a download: you compute the same value on your copy and compare.
The file is read into your browser's memory and hashed with the Web Crypto API (SHA-1, SHA-256, SHA-512) and an MD5 implementation. It is never uploaded; speed depends on your device, and files up to 500 MB are accepted. You can paste the expected value in any common form, with or without spaces, upper or lower case, or a prefix such as “sha256:”.
Which one to compare? Use the algorithm the publisher lists. If several are offered, prefer SHA-256. MD5 and SHA-1 still reveal a corrupted or incomplete download, but they are no longer trusted to prove that nobody altered the file on purpose.
A match shows that your copy equals the file the checksum was calculated from. If the checksum sits on the same page as the download, it does not prove who published it: for software, also check that the page is the vendor's official site over HTTPS.
The same check from a command line: Get-FileHash file.iso -Algorithm SHA256 in Windows PowerShell, certutil -hashfile file.iso SHA256 in Windows cmd, shasum -a 256 file.iso on macOS and sha256sum file.iso on Linux.
Examples
- Linux ISO
- Distributions publish SHA-256 sums next to downloads. Paste it and the tool shows “Match” when the file is intact.
- Installer from a vendor
- Compare the SHA-256 on the vendor's download page with your copy before running the installer.
- Backup copy
- Hash the original and the copy: identical values mean the copy is byte-for-byte the same.
Common uses
- Verifying software and OS downloads
- Checking backup integrity
- Detecting duplicate files
- Confirming a file arrived unchanged after a transfer
Privacy & security
This tool runs entirely in your browser. Your files and text are never uploaded to our servers — processing happens on your device and results are created locally. How each tool handles files
Frequently asked questions
Is the file uploaded?
No. It is read and hashed inside your browser.
What's the maximum size?
Up to 500 MB, depending on your device's memory.
Which checksum should I compare, MD5 or SHA-256?
Use the one the publisher lists. SHA-256 is the safer choice when both are offered: MD5 still catches a corrupted download, but it is no longer trusted to prove a file was not deliberately altered.
The checksums do not match. What now?
Download the file again, preferably from the publisher's own page, and compare again. A mismatch means the file differs from the one that was published, whether through an interrupted download or a change.
Can two different files have the same checksum?
In theory yes, but for SHA-256 and SHA-512 nobody has found a way to make it happen. For MD5 and SHA-1, collisions can be built on purpose, which is why they are not used to prove authenticity.
How do I get a checksum on Windows, Mac or Linux without a tool?
On Windows PowerShell: Get-FileHash file.iso -Algorithm SHA256. On macOS: shasum -a 256 file.iso. On Linux: sha256sum file.iso. This page gives the same result.
Does the checksum change if I rename the file?
No. Only the content counts, not the name, date or location.
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