A checksum is a small piece of data (usually a number or short hash) computed from a bigger block of data. It is used to detect accidental changes, transmission errors, or file corruption.

Which checksum algorithms does this page support?

You can compute CRC32, CRC16/IBM, Adler-32, SUM-8 (mod 256), SUM-16, XOR-8, and, via WebCrypto, MD5 (if available), SHA-1, and SHA-256 for integrity-style hashing.

Can I paste hex data?

Yes. Choose “Hex bytes” in the input type and paste values like AA FF 01 0D or a continuous hex string like AAFF010D.

Checksum Calculator (CRC32, CRC16, Adler32, MD5, SHA)

1. Input data

Select input type and paste your data. Hex can be space/comma separated or continuous.

Input type

Algorithm

CRC Byte order

Affects display only (useful for modbus-style CRC16)

What is a checksum?

A checksum is a very fast way to detect accidental data corruption. You run your data through an algorithm (CRC, Adler, sum, XOR) and get a small numeric value. The receiver recomputes the checksum; if the value differs, the data has been changed.

CRC vs cryptographic hashes

CRC / sums (CRC16, CRC32, SUM-8) are fast and common in serial protocols, CAN, Modbus, embedded logs.
MD5 / SHA are general hash functions (MD5 is considered broken for security, but still used for integrity; SHA-256 is preferred for modern integrity checks).

Common CRC formats

This page uses CRC-32 (0xEDB88320, init 0xFFFFFFFF, final XOR 0xFFFFFFFF) and CRC-16/IBM (poly 0xA001, init 0xFFFF). These match many common tools.

1. Input data

2. Result

What is a checksum?

CRC vs cryptographic hashes

Common CRC formats