Free Online Checksum Calculator
Calculate SHA-256, SHA-1, and SHA-512 checksums for text or files. All computation runs locally using the Web Crypto API.
Key Features
Fast Processing
Uses Web Crypto API for fast, native hash computation.
Privacy Protected
All processing runs locally in your browser. No data sent to servers.
Multiple Algorithms
Compute SHA-256, SHA-1, and SHA-512 checksums individually or all at once.
File Support
Upload files to compute checksums for integrity verification.
Frequently Asked Questions
Getting Started
What is the difference between a checksum and a hash?
Technically a checksum (like CRC32) detects accidental corruption, while a cryptographic hash (like SHA-256) resists intentional tampering. This tool computes cryptographic hashes, not simple checksums.
Should I compare hashes visually?
Never compare hashes visually — a single-character difference is easy to miss. Copy both hashes and use a diff tool, or paste them side by side in a text editor to confirm.
Why no CRC32 or other non-cryptographic checksums?
CRC32 is not available in the Web Crypto API. For verifying file integrity against malicious modification, SHA-256 is the correct tool.
Uppercase or lowercase hex for checksums?
Both are equivalent — hex digits A-F and a-f represent the same values. Linux tools output lowercase, Windows certutil outputs uppercase. The case-toggle button lets you switch instantly.