Is my data sent to any server?

No. All computation happens entirely in your browser using JavaScript. Your input never leaves your device.

Which CRC-16 variant does this use?

This uses CRC-16/IBM (also called CRC-16/ARC): polynomial 0x8005, reflected input/output, initial value 0x0000, no final XOR. Note that Modbus RTU requires CRC-16/MODBUS (which initializes the register to 0xFFFF rather than 0x0000).

Which CRC-32 variant does this use?

This uses CRC-32/ISO-HDLC (also called CRC-32b): polynomial 0x04C11DB7 (0xEDB88320 in reflected form), initial value 0xFFFFFFFF, final XOR 0xFFFFFFFF. This is the same variant used by zlib, gzip, and PNG.

Which CRC-8 variant does this use?

This uses CRC-8/SMBUS: polynomial 0x07, non-reflected, initial value 0x00, no final XOR. This is the most common baseline CRC-8 variant.

What is the hex input format?

Enter bytes as hexadecimal pairs, separated by spaces, commas, or nothing — for example: "DE AD BE EF" or "deadbeef" or "DE,AD,BE,EF". Odd-length sequences are rejected with an error.

Can CRC be used for cryptographic security?

No. CRC is a checksum for error detection, not a cryptographic hash. It is straightforward to craft collisions. For security use SHA-256 or SHA-3.

Can I use CRC-16/CCITT or a custom polynomial?

No. The tool has three fixed presets: CRC-8/SMBUS, CRC-16/ARC and CRC-32/ISO-HDLC. For 123456789, CRC-16/CCITT-FALSE is 0x29B1 and CRC-16/XMODEM is 0x31C3, while this tool's CRC-16 gives 0xBB3D. If your result does not match a device or library, check which variant it uses.

How do I check that my CRC code is correct?

Run it on the ASCII string 123456789, the standard check input. Correct CRC-32 code returns 0xCBF43926, CRC-16/ARC returns 0xBB3D and CRC-8/SMBUS returns 0xF4. Then compare a few of your own inputs here, using Hex Bytes mode for binary data.

CRC Calculator

Compute CRC-8, CRC-16, and CRC-32 checksums from text or raw hex bytes, with results in hex, decimal, and binary.

Type text or paste hex bytes and the CRC appears as you type, in hex, decimal and binary.

Input

Input Mode

Data

CRC Algorithm

CRC-16/ARC (IBM) — poly 0x8005, init 0x0000 (ARC, LHA, USB)

0 bytes

Result

Enter data on the left to compute a checksum.

All Algorithms at a Glance

Enter data above to see all checksums.

Algorithm	Hex	Decimal

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Quick answer

Type text or paste hex bytes and the CRC appears as you type, in hex, decimal and binary. For the standard check string 123456789 the tool gives CRC-32 0xCBF43926, CRC-16/ARC 0xBB3D and CRC-8/SMBUS 0xF4, the published check values for those variants. Use the CRC-8, CRC-16 and CRC-32 buttons to switch.

Examples

Input	CRC-32	CRC-16/ARC
123456789	0xCBF43926	0xBB3D
hello	0x3610A686	0x34D2
Hello, World!	0xEC4AC3D0	0xFA4D
a	0xE8B7BE43	0xE8C1
DE AD BE EF (hex)	0x7C9CA35A	0xE59B

Type text or paste hex bytes.

Summary

This tool computes Cyclic Redundancy Check (CRC) values for CRC-8, CRC-16, and CRC-32 algorithms entirely in your browser. Enter plain text or raw hex bytes and instantly see the checksum in hexadecimal, decimal, and binary representations. CRC checksums are used in network protocols, file formats, and embedded firmware to detect data corruption.

How it works

Choose the input mode — plain text (UTF-8) or raw hex bytes (e.g. DE AD BE EF).
Type or paste your data into the input field.
Select the CRC variant: CRC-8, CRC-16 (IBM), or CRC-32 (ISO-HDLC / zlib).
The checksum updates instantly and is shown in hex, decimal, and binary.
Click any Copy button to copy the desired representation to your clipboard.

Use cases

Verify data integrity after transmission over serial or network links.
Generate test vectors for embedded firmware that uses CRC checks.
Debug communication protocols and file formats that use CRC-16/ARC.
Cross-check CRC output from different programming languages or libraries.
Validate the CRC of a small configuration blob or binary patch segment.
Learn how different CRC polynomials produce different results for the same input.
Quickly compute the CRC of ASCII command strings before sending over UART.
Check that a manually assembled hex byte sequence has the expected checksum.

Frequently Asked Questions

Last updated: 2026-05-28 · Reviewed by Nham Vu