Checksum Calculator
Compute CRC-family checksums for text or encoded bytes, then compare them with an expected value for a quick MATCH/MISMATCH integrity check.
About this tool
CRC checksums are small integrity values used in file formats, storage systems,
network protocols, and embedded devices. Paste text, hex bytes, or base64 bytes,
choose the CRC variant, and this tool returns the checksum in padded hexadecimal
or decimal form. If you already have a checksum from a manifest, device log, or
protocol trace, paste it into Expected checksum to get a clear MATCH or
MISMATCH verdict.
The four built-in variants cover the common cases: CRC-32/ISO-HDLC for ZIP,
gzip, PNG, Ethernet-style checks; CRC-32C/Castagnoli for systems such as
iSCSI and ext4; CRC-16/ARC for classic 16-bit CRC workflows; and
CRC-8/SMBUS for simple 8-bit checks. The standard check string
123456789 produces cbf43926, e3069283, bb3d, and f4 respectively.
This is an error-detection checksum calculator, not a cryptographic hash tool. Use it when a protocol or file format specifically calls for a CRC. For SHA, BLAKE, MD5, or other digests, use the hash tools instead.
Worked example
Input:
123456789
Settings: algorithm = crc32, input_encoding = text, output_format = hex,
expected = cbf43926.
Output:
CRC-32: cbf43926
Expected: cbf43926
Result: MATCH
Limits and edge cases
- Text input is checksummed as UTF-8 bytes. For exact binary data, encode the bytes as hex or standard base64 first.
- Hex input may include whitespace and a leading
0x; base64 input may include whitespace. - Expected values can be hex with or without
0x, any case, or a decimal number. - CRCs detect accidental corruption; they are not safe for passwords, signatures, or tamper-resistant security checks.
FAQ
Which CRC algorithm should I choose?
Use the variant required by the file format or protocol you are checking. ZIP, gzip, PNG, and many Ethernet-style examples usually mean CRC-32/ISO-HDLC. Storage and networking systems that mention Castagnoli usually mean CRC-32C. Older serial or embedded examples often specify a named CRC-16 or CRC-8 variant; this tool provides CRC-16/ARC and CRC-8/SMBUS.
Can I verify a checksum I already have?
Yes. Paste the known checksum into Expected checksum. The tool accepts hex
with or without a 0x prefix, uppercase or lowercase, leading zeros, or a plain
decimal integer, then appends Result: MATCH or Result: MISMATCH.
How do I checksum raw bytes instead of text?
Set Interpret input as to Hex bytes or Base64 bytes, then paste the
encoded bytes. For example, the text bytes for 123456789 are hex
313233343536373839 and base64 MTIzNDU2Nzg5; both decode to the same bytes as
the text input.
Is a CRC the same as a cryptographic hash?
No. CRCs are designed to catch accidental transmission or storage errors. They are fast and useful for compatibility with file formats and protocols, but they are not collision-resistant against an attacker. For cryptographic checksums, use SHA-256 or another digest-oriented hash tool.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool checksum-calculator "123456789"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/checksum-calculator/?text=123456789&algorithm=crc32&input_encoding=text&output_format=hex&uppercase=true&expected=cbf43926Machine-readable descriptor: tool.json — title + parameters JSON Schema for agents.