How to Verify a Downloaded File Is Safe

When you download software, a document, or any file from the internet, how do you know it's the real thing? One of the most reliable ways is to verify its cryptographic checksum.

What is a checksum?

A checksum is a unique string of characters generated from a file's contents. If even a single byte changes — through corruption or malicious tampering — the checksum changes completely. SHA-256 is the industry standard for this verification.

How to check SHA-256

The publisher of the file usually provides the expected SHA-256 hash. You calculate the hash of the file you downloaded and compare the two. If they match exactly, the file is intact. Use our File Hash Checker to calculate SHA-256, SHA-1 and SHA-512 instantly in your browser.

Red flags to watch for

If the checksum doesn't match, do not open the file. Delete it and download again from the official source. Be especially cautious with executables, PDFs from unknown senders, and files from peer-to-peer networks.

Why do this in the browser?

Our tool runs entirely on your device. Your file is never uploaded to a server, which is critical when you're dealing with sensitive or confidential downloads.