Does CRC-16/KERMIT reflect input and output bits?

CRC-16/KERMIT uses RefIn=true and RefOut=true.

CRC-16/KERMIT Calculator

CRC-16/KERMIT is the reflected form of the 0x1021 polynomial used by Kermit data-transfer protocols.

Polynomial: 0x1021
Init: 0x0000
Check (123456789): 0x2189
RefIn / RefOut: true / true

Calculate CRC-16/KERMIT

Input data and input type are stored in the URL so this calculation can be reopened or shared.

⚡ Online CRC Calculator & CRC Lookup Table Generator

Modbus, CCITT, XMODEM 등 표준 CRC 계산, 룩업 테이블(CRC Table) 배열 추출, 소스 코드 및 역산 툴

Engine Active

1. 입력 데이터 (Input Data / Binary File)

Text는 UTF-8 바이트로 변환됩니다.

Calculated result

CRC-16 / KERMIT

Calculated automatically from 9 input bytes.

CRC result

0x2189

Hexadecimal: 0x2189
Decimal: 8585
Binary: 0010000110001001

3. 파라미터 상세 분석 및 커스텀 조작

비트 폭 (Width)

폴리넘얼 (Hex)

초기값 (Init)

최종 XOR (XOR Out)

Reflect InReflect Out

CRC-16 / KERMIT 결과 (Result)0x2189

5. CRC 역산 (Force CRC / Patch Finder)

원하는 최종 CRC 값이 나오도록 데이터 뒤에 채워야 할 패치 바이트(2바이트)를 역산합니다.

계산 대기 중...

4. 순수 룩업 테이블 전용 (CRC Lookup Table Generator)

완벽하게 정렬된 순수 CRC 8/16/32 테이블 배열 텍스트입니다.

복사 완료!

  0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD, 0x6536, 0x74BF, 
  0x8C48, 0x9DC1, 0xAF5A, 0xBED3, 0xCA6C, 0xDBE5, 0xE97E, 0xF8F7, 
  0x1081, 0x0108, 0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E, 
  0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64, 0xF9FF, 0xE876, 
  0x2102, 0x308B, 0x0210, 0x1399, 0x6726, 0x76AF, 0x4434, 0x55BD, 
  0xAD4A, 0xBCC3, 0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5, 
  0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E, 0x54B5, 0x453C, 
  0xBDCB, 0xAC42, 0x9ED9, 0x8F50, 0xFBEF, 0xEA66, 0xD8FD, 0xC974, 
  0x4204, 0x538D, 0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB, 
  0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1, 0xAB7A, 0xBAF3, 
  0x5285, 0x430C, 0x7197, 0x601E, 0x14A1, 0x0528, 0x37B3, 0x263A, 
  0xDECD, 0xCF44, 0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72, 
  0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB, 0x0630, 0x17B9, 
  0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5, 0xA96A, 0xB8E3, 0x8A78, 0x9BF1, 
  0x7387, 0x620E, 0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738, 
  0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862, 0x9AF9, 0x8B70, 
  0x8408, 0x9581, 0xA71A, 0xB693, 0xC22C, 0xD3A5, 0xE13E, 0xF0B7, 
  0x0840, 0x19C9, 0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF, 
  0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324, 0xF1BF, 0xE036, 
  0x18C1, 0x0948, 0x3BD3, 0x2A5A, 0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E, 
  0xA50A, 0xB483, 0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5, 
  0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF, 0x4C74, 0x5DFD, 
  0xB58B, 0xA402, 0x9699, 0x8710, 0xF3AF, 0xE226, 0xD0BD, 0xC134, 
  0x39C3, 0x284A, 0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C, 
  0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1, 0xA33A, 0xB2B3, 
  0x4A44, 0x5BCD, 0x6956, 0x78DF, 0x0C60, 0x1DE9, 0x2F72, 0x3EFB, 
  0xD68D, 0xC704, 0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232, 
  0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68, 0x3FF3, 0x2E7A, 
  0xE70E, 0xF687, 0xC41C, 0xD595, 0xA12A, 0xB0A3, 0x8238, 0x93B1, 
  0x6B46, 0x7ACF, 0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9, 
  0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022, 0x92B9, 0x8330, 
  0x7BC7, 0x6A4E, 0x58D5, 0x495C, 0x3DE3, 0x2C6A, 0x1EF1, 0x0F78

Model: CRC-16 / KERMITCRC Table & Lookup Array

6. 언어별 전체 함수 소스 코드 및 CRC Table (C Source)

CRC-16 / KERMIT

복사 완료!

/* 
 * Model: CRC-16 / KERMIT (16-bit)
 * Poly: 0x1021, Init: 0x0000, XorOut: 0x0000
 * CRC Table C Source Code & Lookup Table Generator
 */
#include <stdint.h>
#include <stddef.h>

const uint16_t crc_table[256] = {
  0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD, 0x6536, 0x74BF, 
  0x8C48, 0x9DC1, 0xAF5A, 0xBED3, 0xCA6C, 0xDBE5, 0xE97E, 0xF8F7, 
  0x1081, 0x0108, 0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E, 
  0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64, 0xF9FF, 0xE876, 
  0x2102, 0x308B, 0x0210, 0x1399, 0x6726, 0x76AF, 0x4434, 0x55BD, 
  0xAD4A, 0xBCC3, 0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5, 
  0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E, 0x54B5, 0x453C, 
  0xBDCB, 0xAC42, 0x9ED9, 0x8F50, 0xFBEF, 0xEA66, 0xD8FD, 0xC974, 
  0x4204, 0x538D, 0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB, 
  0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1, 0xAB7A, 0xBAF3, 
  0x5285, 0x430C, 0x7197, 0x601E, 0x14A1, 0x0528, 0x37B3, 0x263A, 
  0xDECD, 0xCF44, 0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72, 
  0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB, 0x0630, 0x17B9, 
  0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5, 0xA96A, 0xB8E3, 0x8A78, 0x9BF1, 
  0x7387, 0x620E, 0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738, 
  0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862, 0x9AF9, 0x8B70, 
  0x8408, 0x9581, 0xA71A, 0xB693, 0xC22C, 0xD3A5, 0xE13E, 0xF0B7, 
  0x0840, 0x19C9, 0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF, 
  0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324, 0xF1BF, 0xE036, 
  0x18C1, 0x0948, 0x3BD3, 0x2A5A, 0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E, 
  0xA50A, 0xB483, 0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5, 
  0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF, 0x4C74, 0x5DFD, 
  0xB58B, 0xA402, 0x9699, 0x8710, 0xF3AF, 0xE226, 0xD0BD, 0xC134, 
  0x39C3, 0x284A, 0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C, 
  0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1, 0xA33A, 0xB2B3, 
  0x4A44, 0x5BCD, 0x6956, 0x78DF, 0x0C60, 0x1DE9, 0x2F72, 0x3EFB, 
  0xD68D, 0xC704, 0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232, 
  0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68, 0x3FF3, 0x2E7A, 
  0xE70E, 0xF687, 0xC41C, 0xD595, 0xA12A, 0xB0A3, 0x8238, 0x93B1, 
  0x6B46, 0x7ACF, 0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9, 
  0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022, 0x92B9, 0x8330, 
  0x7BC7, 0x6A4E, 0x58D5, 0x495C, 0x3DE3, 0x2C6A, 0x1EF1, 0x0F78
};

uint16_t calculate_crc(const uint8_t *data, size_t length) {
    uint16_t crc = 0x0000;
    for (size_t i = 0; i < length; i++) {
        #if 1
        uint8_t idx = (uint8_t)(crc ^ data[i]);
        crc = (crc >> 8) ^ crc_table[idx];
        #else
        uint8_t idx = (uint8_t)((crc >> 8) ^ data[i]);
        crc = (crc << 8) ^ crc_table[idx];
        #endif
    }
    return crc ^ 0x0000;
}

About CRC-16/KERMIT

Standard test vector

CRC implementations are commonly verified with the ASCII input 123456789. For CRC-16/KERMIT, the expected result is 0x2189.

Input format: ASCII
Input: 123456789
Expected CRC: 0x2189
Residue: 0x0000

How this model differs

A CRC name identifies the complete parameter set, not only its polynomial. Implementations must match width, Init, RefIn, RefOut, and XorOut to reproduce the published check value.

Bit order: Reflected
Register start: 0x0000
Final XOR: 0x0000
Published check: 0x2189

Parameter reference

Complete CRC-16/KERMIT parameters

CRC parameter guide →

Parameter	Value	Meaning	Learn
Width	16 bits	CRC register and result width	Read guide →
Poly	0x1021	Generator polynomial without the leading term	Read guide →
Init	0x0000	Initial CRC register value	Read guide →
RefIn	true	Reflect each input byte before processing	Read guide →
RefOut	true	Reflect the register before XOR Out	Read guide →
XorOut	0x0000	Final value XORed with the CRC register	Read guide →
Check	0x2189	CRC of ASCII “123456789”	Read guide →
Residue	0x0000	Expected residue after appending a valid CRC	Read guide →

Also known as:CRC-CCITT KERMITCRC16 KERMIT

Where CRC-16/KERMIT is used

Kermit
Legacy communications
Embedded protocols

CRC-16/KERMIT FAQ

What is the check value for CRC-16/KERMIT?

For the standard ASCII test input 123456789, the check value is 0x2189.

What polynomial does CRC-16/KERMIT use?

It uses the 16-bit polynomial 0x1021.

Does CRC-16/KERMIT use reflected input and output?

RefIn=true and RefOut=true.

Online CRC Calculator and CRC Lookup Table Generator

This free online CRC calculator computes CRC-8, CRC-16, and CRC-32 checksums from UTF-8 text, hexadecimal, decimal-byte, binary-bit, Base64 input, or binary files. You can select common preset algorithms such as CRC-16/MODBUS, CRC-16/CCITT-FALSE, CRC-16/XMODEM, CRC-16/KERMIT, and CRC-32/ISO-HDLC, or define custom CRC parameters for your own protocol.

The calculator also generates CRC lookup tables and complete source code for C, Python, and JavaScript. All calculations are performed locally in your browser, so uploaded files and input data are not sent to a server.

Supported CRC parameters

Custom CRC calculations can be configured using width, polynomial, initial value, input reflection, output reflection, and final XOR value. These parameters allow the calculator to reproduce many standard and proprietary CRC implementations used in embedded systems, serial communication, industrial protocols, file formats, and network applications.

Width: Defines the CRC register size, such as 8, 16, or 32 bits.
Polynomial: Specifies the generator polynomial used by the CRC algorithm.
Initial value: Sets the value loaded into the CRC register before processing data.
RefIn and RefOut: Control whether input bytes and the final CRC result are reflected.
Final XOR value: Applies a final XOR operation to the CRC register before displaying the checksum.

CRC-8, CRC-16, and CRC-32

CRC-8 produces an 8-bit checksum and is commonly used in compact embedded and sensor protocols. CRC-16 produces a 16-bit checksum and is widely used by protocols such as Modbus, XMODEM, and CCITT-based communication systems. CRC-32 produces a 32-bit checksum and provides stronger error detection for larger files, archives, Ethernet frames, and storage formats.

CRC lookup table and source code generator

A CRC lookup table replaces repeated bit-by-bit polynomial operations with precomputed values. This can significantly improve checksum performance in firmware, embedded software, and high-throughput applications. The generated table and function code can be copied directly into C, Python, or JavaScript projects and adapted as needed.

Frequently asked questions

What is a CRC checksum?

A cyclic redundancy check, or CRC, is an error-detection method used to identify accidental changes in transmitted or stored data. The sender calculates a CRC value, and the receiver calculates it again to verify that the data has not been corrupted.

Which CRC algorithm should I use?

Use the algorithm required by your protocol or file format. For example, Modbus commonly uses CRC-16/MODBUS, while other systems may require CCITT-FALSE, XMODEM, KERMIT, CRC-32, or a custom parameter set.

Why do CRC calculators sometimes return different results?

CRC results depend on more than the polynomial. Width, initial value, input reflection, output reflection, final XOR value, input encoding, and byte order must all match. A difference in any one of these settings can produce a different checksum.

Can I calculate the CRC of a binary file?

Yes. Select the file input option and choose a binary file. The calculator reads the file as bytes and computes the selected CRC directly in your browser.

Are uploaded files sent to a server?

No. CRC calculations and file processing are performed locally in the browser. Your files and input data are not uploaded to the website server.

What is the standard CRC check value for 123456789?

The ASCII string 123456789 is commonly used as a standard CRC test input. The expected result depends on the selected algorithm. For example, CRC-32/ISO-HDLC produces 0xCBF43926, while CRC-16/MODBUS produces 0x4B37.

CRC-16/KERMIT Calculator

Calculate CRC-16/KERMIT

1. 입력 데이터 (Input Data / Binary File)

CRC-16 / KERMIT

3. 파라미터 상세 분석 및 커스텀 조작

5. CRC 역산 (Force CRC / Patch Finder)

4. 순수 룩업 테이블 전용 (CRC Lookup Table Generator)

6. 언어별 전체 함수 소스 코드 및 CRC Table (C Source)

About CRC-16/KERMIT

Standard test vector

How this model differs

Complete CRC-16/KERMIT parameters

Where CRC-16/KERMIT is used

CRC-16/KERMIT FAQ

What is the check value for CRC-16/KERMIT?

What polynomial does CRC-16/KERMIT use?

Does CRC-16/KERMIT use reflected input and output?

Guides for CRC-16/KERMIT

What is a CRC checksum?

CRC polynomial explained

CRC initial value (Init)

CRC reflection: RefIn and RefOut

CRC final XOR (XorOut)

CRC check value and “123456789”

CRC residue explained

CRC byte order and endianness

Related CRC calculators

Online CRC Calculator and CRC Lookup Table Generator

Supported CRC parameters

CRC-8, CRC-16, and CRC-32

CRC lookup table and source code generator

Frequently asked questions