Is my text, hex input, or file uploaded for calculation?

No. The calculator does not send that input to a checksum endpoint. Text is encoded as UTF-8, hex is decoded into bytes in memory, and selected files are read locally through FileReader.

How does Hex mode handle formatting like spaces or 0x prefixes?

Hex mode strips whitespace, commas, colons, newlines, and "0x" byte prefixes. It requires valid hexadecimal characters ([0-9a-fA-F]) and complete two-character byte pairs.

Are MD5 and SHA-1 secure for cryptographic validation?

No. Per RFC 6151 and FIPS 180-4, MD5 and SHA-1 suffer from demonstrated collision weaknesses. They are provided solely for non-adversarial legacy file integrity checks, never for password storage or digital signatures.

What are the file size and browser limitations?

In-browser SubtleCrypto.digest requires the complete byte buffer in memory, limiting reliable client file processing to 256 MB. Browsers require a secure context (HTTPS or localhost) for SubtleCrypto.

Which CRC-32 variant does the calculator use?

It uses the reflected 0xEDB88320 polynomial with an initial value and final XOR of 0xFFFFFFFF. The check value for the ASCII bytes “123456789” is CBF43926.

Checksum Calculator

Enter UTF-8 text, paste raw hexadecimal byte strings, or load a local file up to 256 MB to compute MD5, SHA-1, SHA-256, SHA-512, and CRC-32 digests without server uploads.

Input

0 bytes

Security advisory: MD5 and SHA-1 are legacy algorithms with collision weaknesses. Use them only to match an existing checksum, never for passwords, authentication, or digital signatures. References: RFC 6151 · Web Crypto digest() · NIST FIPS 180-4

Digests & Checksums

Enter text, hex bytes, or choose a file to compute checksums

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Summary

Enter UTF-8 text, paste raw hexadecimal byte strings, or load a local file up to 256 MB to compute MD5, SHA-1, SHA-256, SHA-512, and CRC-32 digests without server uploads.

How it works

Select an input mode: UTF-8 Text, raw Hexadecimal byte stream, or local File.
Hex mode normalizes byte streams by stripping whitespace, commas, colons, and 0x prefixes while validating byte-pair parity.
SHA-1, SHA-256, and SHA-512 digests are generated via the browser Web Cryptography API (SubtleCrypto).
MD5 (RFC 1321) and CRC-32 (reflected polynomial 0xEDB88320) execute locally in JavaScript.
Compare generated digests against any published checksum using case-insensitive prefix-tolerant matching.

Use cases

Verify build artifacts and downloads against published SHA-256 or legacy MD5 checksums.
Calculate CRC-32 or SHA-256 digests for raw hexadecimal payloads in industrial, SCADA, or network packet traces.
Compute digests for firmware binary patches supplied as formatted hex strings.
Check file integrity prior to software installation or archiving.
Validate message digest parity between developmental environments and cryptographic test vectors.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu