Generate a SHA-256 Checksum for Any File
A checksum is a file's fingerprint: run the same file through SHA-256 anywhere and you get the same 64-character value, but change a single byte and the value changes completely. This tool computes checksums by streaming the file through the hash function locally — files of any size work, memory use stays flat, and nothing is uploaded.
The actual tool runs in our ad-free secure workspace — nothing on this page processes your file.
Open File Hash Generator →What this tool does
- Computes SHA-256, SHA-384, and SHA-512 checksums for any file type.
- Streams files through the hash in chunks, so multi-gigabyte files hash with constant memory use.
- Also offers MD5 and SHA-1 strictly for comparing against legacy published values — with a clear warning that both are cryptographically broken.
- Hashes multiple files in a batch and lets you export a checksum manifest for the whole set.
- Copies results in the standard lowercase-hex format used by sha256sum and release pages everywhere.
Your privacy on this tool
Stays on your device
- Files are read and hashed entirely on your device — only the resulting fingerprint appears on screen.
- No file content, file name, or computed hash is transmitted or logged.
- Hashing works offline once the page is loaded.
Reaches our server: nothing
This tool makes no upload. Your content is processed entirely in your browser.
How to use it
- Open the tool at /app/file-hash.
- Drop in one or more files — size is not a constraint, since hashing streams.
- Pick the algorithm; SHA-256 is the standard choice unless you have a reason otherwise.
- Copy the resulting checksum, or export a manifest covering every file in the batch.
- Publish or store the checksum alongside the file so others (or future you) can verify it.
Common uses
- Publishing a checksum next to a file you distribute, so downloaders can verify what they received.
- Fingerprinting important archives before long-term storage, to detect bit rot or tampering years later.
- Confirming two large files are identical without comparing them byte by byte across machines.
- Recording evidence integrity — hashing files at collection time so any later change is provable.
- Generating a manifest for a folder of deliverables handed to a client.
Supported formats
- Any file type
- Output: SHA-256 / SHA-384 / SHA-512 (MD5 and SHA-1 legacy-only, with warnings)
Runs in all modern browsers via WebAssembly; large-file hashing is fastest in desktop Chrome, Edge, and Firefox.
Limitations & security notes
Limitations
- A checksum verifies integrity, not safety — malware hashes just as cleanly as legitimate software. It proves the file is unchanged, not that it is good.
- Checksums have no key: anyone who can alter your file can publish a matching new checksum beside it. Authenticity requires signatures, which are out of scope here.
- MD5 and SHA-1 are provided only because old release pages still publish them; collisions are practical for both, so never choose them for new purposes.
- SecretPNG is in beta and has not been independently audited.
Security notes
- SHA-256 remains collision-resistant by every public measure — finding two files with the same hash is beyond known capability, which is exactly what makes the fingerprint trustworthy.
- Store or publish checksums somewhere separate from the file itself; a checksum sitting next to a tampered file on the same compromised server verifies nothing.
- The legacy-algorithm warnings are not decoration: MD5 collisions can be generated in seconds on a laptop, and SHA-1's SHAttered attack made its weakness concrete.
- For verifying a file against a published value, the companion verifier tool compares for you — safer than eyeballing 64 hex characters.
Frequently asked questions
- What does a SHA-256 checksum actually prove?
- That two files are (for all practical purposes) identical. If your computed value matches the published one, you have the exact bytes the publisher hashed — no corruption, no truncation, no tampering in transit. What it cannot prove is who published it or whether the original file was trustworthy; for that you need signatures.
- Can two different files have the same SHA-256 hash?
- In theory, collisions must exist because files outnumber 256-bit values. In practice, nobody has ever found one, and the estimated work to do so exceeds any plausible computing capability. For integrity purposes, treat matching SHA-256 values as proof of identical files.
- Why do you even offer MD5 and SHA-1 if they're broken?
- Because reality is messy: plenty of older software releases and archives only published MD5 or SHA-1 values, and comparing against them is still better than not verifying at all. The tool labels them as legacy and warns you at every turn — use them to check old published values, never to fingerprint anything new.
- How can a browser hash a 20 GB file without uploading it?
- Hash functions digest data incrementally: the tool reads the file from your disk in chunks, feeds each chunk to the hash state, and discards it. Only the running state — a few dozen bytes — stays in memory, and only the final fingerprint is displayed. The file never needs to be anywhere but your own disk.
- Which algorithm should I pick?
- SHA-256, unless something specific dictates otherwise. It is the de facto standard for file distribution, universally supported, and comfortably secure. SHA-384 and SHA-512 are fine choices too — SHA-512 can even be faster on 64-bit desktops — but SHA-256 is what the person verifying your file will expect.
Related tools
Last reviewed: 2026-07-14Open File Hash Generator
SecretPNG is in beta and has not been independently audited. Security status.