Checksum Calculator

SHA-1 / SHA-256 / SHA-384 / SHA-512 — computed locally in your browser

File

The file stays on your device — only the checksum is shown.

Try it with a sample file

Download sample file

Then load it above. The SHA-256 should be exactly:

26abf6c87fc6c38f9b64e7f29417a1555e5c7f80eb63150760c3ce254683c686

SHA-1: bf886a39215bd4a1be067d75873a48437d25f7d9

ℹ️ MD5 is not available — the browser Web Crypto API only supports SHA algorithms (SHA-1/256/384/512). For MD5 use a dedicated hashing tool.

About

Compute a cryptographic checksum (hash) of any file using the browser's native Web Crypto API. Supports SHA-1, SHA-256, SHA-384 and SHA-512. The file is read locally and never uploaded — the hash is computed entirely in your browser. Useful for verifying download integrity or detecting file changes. MD5 is not supported by the Web Crypto API.

    Examples

    Compute SHA-256 of a file

    Input
    file: contract.pdf (1.2 MB)
algorithms: SHA-256, SHA-512
    Output
    SHA-256: 9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08
SHA-512: ee26b0dd4af7e749aa1a8ee3c10ae9923f618980772e473f8819a5d4940e0db27ac185f8a0e1d5f84f88bc887fd67b143732c304cc5fa9ad8e6f57f50028a8ff

    Two strong SHA-2 digests are computed from the same file digest for cross-checking, version verification, or signature validation.

    Verify a downloaded ISO

    Input
    downloaded file: ubuntu-24.04.iso
published SHA-256:  ...a7b4...
    Output
    Match: ✓
SHA-256: <your computed digest>

    Compute the digest locally and compare it against the publisher's checksum to confirm the download was not corrupted or tampered with.

    About this tool

    The Checksum Calculator computes SHA-1, SHA-256, SHA-384 and SHA-512 digests of text and files using the browser's native Web Crypto API. SHA-256 and SHA-512 are recommended for any security-sensitive use; SHA-1 is included for legacy compatibility but should not be used where collision resistance matters.

    All hashing runs in your browser. Files are streamed through the SubtleCrypto digest() primitive without being uploaded, so it is safe to verify the integrity of internal documents, installers, and large datasets without leaving a trace.

    How to use

    1. Enter your input

      Type or paste text, or drop in a file. Large files are supported but held in memory for the read.

    2. Read the digests

      The tool computes every selected algorithm at once and shows the hexadecimal digests side by side.

    3. Verify a checksum

      Copy a digest and compare it against a publisher's published checksum, or save it as a fingerprint of the content.

    Use cases

    Verifying downloads

    Compute the SHA-256 of an installer, ISO, or archive and compare it against the publisher's published checksum before running the file.

    Fingerprinting content

    Generate a stable hash for a document, build artifact, or dataset so a duplicate or changed version can be detected without storing the full content.

    Checking integrity after transfer

    Hash a file before and after copying it to a backup, USB drive, or remote server to confirm the copy matches byte-for-byte.

    Common mistakes

    Mistake:Using SHA-1 for any security-sensitive purpose.

    Fix:SHA-1 has known collision attacks. Use SHA-256 or SHA-512 for integrity verification, signatures, and any security-sensitive work.

    Mistake:Expecting MD5 to be available.

    Fix:The browser's Web Crypto API does not expose MD5. Use a separate tool for MD5 and never rely on it for security — it is broken for collision resistance.

    Mistake:Hashing on the server after upload.

    Fix:Hashing on the client (in this tool) means the file never has to be uploaded for verification. Pair the local hash with a published checksum to confirm integrity without leaving your machine.

    Frequently asked questions

    References & standards

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