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How File Hash Calculator works

  1. Click the file selection area and choose any file from your device.
  2. Watch the progress bar as the file is read and hashed.
  3. View the SHA-1, SHA-256, and SHA-512 hash values once complete.
  4. Click Copy next to any hash to copy it to your clipboard.
  5. Compare the copied hash against a publisher's reference checksum to verify file integrity.
  • Verify a downloaded software installer matches the checksum published on the vendor's website.
  • Confirm two files are byte-for-byte identical by comparing their SHA-256 hashes.
  • Generate a checksum to include alongside a file you're distributing so others can verify it.
  • Check that a large file transfer completed without corruption.
  • Produce a reference hash for a file used in a security or compliance audit.

The file is read and hashed entirely in your browser using the File API and Web Crypto API's SubtleCrypto. It is never uploaded or transmitted to a server.

  • The entire file is loaded into browser memory at once, so very large files (multiple GB) may slow down or crash the tab depending on available RAM.
  • SHA-1 is included for compatibility but is not collision-resistant against a determined attacker — prefer SHA-256 or SHA-512 for security-sensitive verification.
  • Only one file can be hashed at a time; there's no batch or folder hashing.

File Hash Calculator

File Hash Calculator computes cryptographic hash values for any file using the Web Crypto API. Drop a file of any type, and SHA-1, SHA-256, and SHA-512 hashes are calculated locally using SubtleCrypto.digest(). A progress bar tracks the hashing process for large files.

File Hash Calculator Runs locally

Drop a file to hash
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Guide

How to use

  1. Click the file selection area and choose any file from your device.

  2. Watch the progress bar as the file is read and hashed.

  3. View the SHA-1, SHA-256, and SHA-512 hash values once complete.

  4. Click Copy next to any hash to copy it to your clipboard.

  5. Compare the copied hash against a publisher's reference checksum to verify file integrity.

Scenarios

Use cases

  • Verify a downloaded software installer matches the checksum published on the vendor's website.

  • Confirm two files are byte-for-byte identical by comparing their SHA-256 hashes.

  • Generate a checksum to include alongside a file you're distributing so others can verify it.

  • Check that a large file transfer completed without corruption.

  • Produce a reference hash for a file used in a security or compliance audit.

Good to know

Limitations & Privacy

Private by design

The file is read and hashed entirely in your browser using the File API and Web Crypto API's SubtleCrypto. It is never uploaded or transmitted to a server.

  • The entire file is loaded into browser memory at once, so very large files (multiple GB) may slow down or crash the tab depending on available RAM.

  • SHA-1 is included for compatibility but is not collision-resistant against a determined attacker — prefer SHA-256 or SHA-512 for security-sensitive verification.

  • Only one file can be hashed at a time; there's no batch or folder hashing.

FAQ

Frequently asked questions

What is a file hash used for?

File hashes (checksums) verify file integrity. By comparing a computed hash against a published reference hash, you can confirm a downloaded file has not been corrupted or tampered with in transit.

Is my file uploaded anywhere?

No. The file is read entirely in your browser using the File API's arrayBuffer() method and hashed locally using the Web Crypto API's SubtleCrypto.digest(). Nothing is transmitted over the network.

Which hash algorithms does this support?

SHA-1, SHA-256, and SHA-512, computed simultaneously for whatever file you select. SHA-256 is the most commonly published checksum for software downloads today.

Why compute SHA-1 if it's considered broken?

SHA-1 is no longer considered cryptographically secure against deliberate collision attacks, but it's still widely published for basic file integrity checks (like Git's internal object hashing) where an adversarial collision isn't the threat model.

How large a file can I hash?

There's no artificial limit — the whole file is read into an ArrayBuffer in memory, so practical limits depend on your device's available RAM. Very large files (multiple GB) may cause the browser tab to slow down or run out of memory.

Why does hashing take a moment for large files?

The file must be fully read into memory and then processed by three separate hash algorithms in sequence. The progress bar reflects reading the file (first half) and computing each algorithm's digest (second half).

Can I hash multiple files at once?

No, the tool processes one file at a time. Select a new file to clear the previous results and hash the new one.