File Checksum Calculator

Calculate cryptographic checksums for any file using the Web Crypto API. Nothing is uploaded — all processing happens in your browser.

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Drop a file here or click to select

Any file type, any size

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🔍 Verify Checksum

Paste an expected hash to compare against the calculated result.

About This Tool

Uses the browser's native Web Crypto API for fast, secure hashing. Your file never leaves your device.

When to Use

  • Verify downloaded files
  • Compare files for identity
  • Detect file corruption

How File Checksums Work

A checksum is a fixed-size string generated from file contents using a cryptographic hash function. Even a 1-byte change produces a completely different hash, making it perfect for verifying that a file has not been altered.

Frequently Asked Questions

No. The file is processed entirely in your browser using the Web Crypto API.

SHA-256 is the most common. Use SHA-512 for extra security. SHA-1 is deprecated for security but still used in legacy systems.