Does CRC-16 upload my file or text to Tool-You servers?

No. CRC-16 runs in this browser tab. Files stay on the device. Limit note: Non-empty UTF-8. Optional uppercase. Local only.

Should I use CRC-32 instead of CRC-16?

Use CRC-16 when you need CRC-16/CCITT; optional uppercase hex. Use CRC-32 when you need IEEE CRC-32; optional uppercase hex. They share a category (Crypto) but not the same job.

CRC-16

CRC-16/CCITT; optional uppercase hex.

CRC-16 (poly 0x1021) of UTF-8. Optional uppercase. Unlike CRC-32 this is 16-bit. Empty text fails. Local only.

What CRC-16 does

CRC-16 (poly 0x1021) of UTF-8. Optional uppercase. Unlike CRC-32 this is 16-bit. Empty text fails. Local only.

The interactive controls for CRC-16 load after this article so crawlers still read the instructions. Path /crypto/crc16 is the canonical address. Work happens on this device; Tool-You does not take a copy of the file or pasted text for CRC-16.

How to use CRC-16

Keep this tab on CRC-16 (/crypto/crc16). Pasting into the wrong Crypto tool (for example CRC-32) changes the job.
Paste or type the input CRC-16 expects. Path hint: crypto · crc16. CRC-16/CCITT; optional uppercase hex.
Apply the CRC-16 action only. Adler-32 is a different transform (Adler-32 checksum; optional uppercase hex.). CRC-16 (poly 0x1021) of UTF-8. Optional uppercase. Unlike CRC-32 this is 16-bit. Empty text fails. Local only.
Copy the output of CRC-16 if you need it elsewhere. Size/complexity still follows: Non-empty UTF-8. Optional uppercase. Local only.
If the text job is actually IEEE CRC-32; optional uppercase hex., leave CRC-16 and open CRC-32.

When not to use CRC-16

Skip CRC-16 when a neighbor tool matches better — start with CRC-32 or Adler-32 — or when the description already warns the job will fail. In the tool’s own words: CRC-16 (poly 0x1021) of UTF-8. Optional uppercase. Unlike CRC-32 this is 16-bit. Empty text fails. Local only.

Questions about CRC-16

What does CRC-16 do that other Crypto pages on this site do not?: CRC-16 (poly 0x1021) of UTF-8. Optional uppercase. Unlike CRC-32 this is 16-bit. Empty text fails. Local only. Short version: CRC-16/CCITT; optional uppercase hex.
Does CRC-16 upload my file or text to Tool-You servers?: No. CRC-16 runs in this browser tab. Files stay on the device. Limit note: Non-empty UTF-8. Optional uppercase. Local only.
Should I use CRC-32 instead of CRC-16?: Use CRC-16 when you need CRC-16/CCITT; optional uppercase hex. Use CRC-32 when you need IEEE CRC-32; optional uppercase hex. They share a category (Crypto) but not the same job.
What are the limits of CRC-16?: Non-empty UTF-8. Optional uppercase. Local only. Also: CRC-16 (poly 0x1021) of UTF-8. Optional uppercase. Unlike CRC-32 this is 16-bit. Empty text fails. Local only.