Checksum Calculator
Calculate SHA checksums for pasted text or local files with optional expected-value verification and hex or Base64 output. Perfect for release verification, integrity checks, file-transfer debugging, and deployment workflows.
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What is Checksum Calculator?
The Checksum Calculator computes cryptographic hash values for files or text using MD5, SHA-1, SHA-256, and SHA-512 algorithms. Checksums are used to verify that a file has not been corrupted or tampered with. You upload a file or enter text, select an algorithm, and the tool produces the hash. All processing happens in the browser.
How does Checksum Calculator work?
This tool uses the browser's SubtleCrypto API to compute SHA hashes and a JavaScript library for MD5. It reads file contents as an ArrayBuffer, processes them through the selected algorithm, and outputs the hash as a lowercase hexadecimal string.
Key Features
- Supports MD5, SHA-1, SHA-256, SHA-512
- File and text input
- Hexadecimal output
- Copy hash to clipboard
- Compare two hashes
- Drag-and-drop file upload
- Runs in the browser with no uploads
- Real-time computation
Common Use Cases
Verifying downloaded files
Compare a file's checksum with the published value to confirm it downloaded correctly.
Detecting file corruption
Generate a checksum before and after transfer to verify the file was not corrupted.
Creating file fingerprints
Generate unique hash identifiers for files in a database or catalog.
Checking for duplicate files
Hash two files and compare the results to check if their contents are identical.
How to Use This Tool
Upload a file or enter text
Drag and drop a file or type text into the input area.
Select algorithm
Choose MD5, SHA-1, SHA-256, or SHA-512.
Calculate
Click Calculate to compute the checksum.
Copy or compare
Copy the hash or enter a second hash to compare.
Pro Tips
- 1
SHA-256 is the recommended algorithm for security-sensitive applications.
- 2
MD5 is fast but not collision-resistant. Use it for integrity checks, not security.
- 3
The same input always produces the same hash.
- 4
Even a one-byte change in a file produces a completely different hash.
Frequently Asked Questions
What is a checksum?
A checksum is a fixed-length string produced by a hash algorithm. It acts as a digital fingerprint for data. If the data changes, the checksum changes.
Which algorithm should I use?
SHA-256 for security. MD5 for quick integrity checks. SHA-512 for maximum security.
Is my data sent to a server?
No. All computation happens in your browser. Nothing is transmitted.
Can I hash large files?
Yes. The tool handles files of any size that fit in browser memory. Large files may take a moment.
What is the difference between checksum and hash?
They are used interchangeably. A checksum specifically refers to using a hash to verify data integrity.