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CRC-16 Checksum Calculator
CRC-16 cyclic redundancy check calculator supporting multiple CRC-16 algorithms
Calculation Result Details
CRC-16/ARC · 9 bytes
Online CRC-16 Calculator for Text and Hex Bytes
Calculate a 16-bit cyclic redundancy check from UTF-8 text or exact hexadecimal bytes. Select the profile required by your device or protocol; CRC-16 is a family of parameter sets, not one universal algorithm.
Supported CRC-16 profiles
| Profile | Poly | Init | RefIn / RefOut | Check (123456789) |
|---|---|---|---|---|
| CRC-16/ARC | 0x8005 |
0x0000 |
true / true | 0xBB3D |
| CRC-16/CCITT-FALSE | 0x1021 |
0xFFFF |
false / false | 0x29B1 |
| CRC-16/MODBUS | 0x8005 |
0xFFFF |
true / true | 0x4B37 |
| CRC-16/XMODEM | 0x1021 |
0x0000 |
false / false | 0x31C3 |
All profiles use XorOut = 0x0000. The standard check string makes it easy to compare this calculator with a device specification or another implementation.
How to use the calculator
- Choose the exact CRC-16 profile.
- Use Text / UTF-8 for normal text, or Hex bytes for packet data.
- Enter the data and calculate the checksum.
- Copy the hexadecimal result or download the full result details.
Hex mode accepts complete byte pairs separated by spaces, commas, colons or hyphens. For example, 31 32 33 is the byte sequence for ASCII 123.
Modbus CRC byte order
For the standard check string, CRC-16/MODBUS is 0x4B37. A Modbus RTU frame appends the low byte first, so the transmitted bytes are 37 4B. This wire order does not change the numeric checksum.
Frequently asked questions
Why do two CRC-16 tools return different results?
They may use different Poly, Init, RefIn, RefOut or XorOut settings, or one tool may interpret text while the other reads hexadecimal bytes.
Is CRC-16 encryption?
No. CRC-16 detects many accidental data errors but does not protect against intentional modification.
Is input data uploaded?
No. Text encoding and CRC calculation run locally in your browser.