If you are creating a QR Code using Design & Print Online, you are able to enter up to 4,000 characters, but it's very important that you check to be sure the QR Code can be successfully scanned. Successful scanning is based on the size of the QR Code, the number of characters that are included, and the accuracy of the printer. Create larger size codes if you have many characters to scan, such as the 8" square Avery sign sheets.
Note: The more characters added to the coding, the smaller the squares in the code get and will eventually become un-scannable when printed.