Chrome and Mac OS X print paper sizes are set to US Letter format by default. If your labels are not printing the correct size, it may be necessary to adjust the print settings for Chrome and/or Mac OS X.
It is important to note, that while Chrome does not allow a default Paper size to be set, Chrome's Paper size setting will remain the same until manually changed. Alternatively, you can print using the MAC OS X System Dialog and customize the default settings to your needs.
To set the print paper size for Chrome and Mac OS X, or resolve label print size issues, follow the steps below.
Note: Mac OS X 10.6 and earlier will not let you set a custom default print size.
Mac OS Print settings
Click “Print using system dialog”. This is on the left-hand side in the form of a blue link. (You may need to scroll down to see it.)
Click the menu next to Paper Size, then select “Manage custom sizes”.
Click the "+ "sign (bottom left) to create a new paper size.
Change the name by double-clicking on "Untitled". We recommend changing the name to something you will remember, such as "4x6".
Leave the "Non-Printable Area" set to "User Defined" and change the margins if necessary - we suggest a very small margin or no margin. Click "OK "to return to the print dialogue box.
Back on the Print Dialog screen, click “Cancel”.
Navigate to System Preferences on your Mac.
Click on “Printers & Scanners”.
Set the Default paper size to the 4x6 template you just created, by selecting the name you assigned it. You can also set the default printer if you prefer.
Chrome Print settings
In Google Chrome press Command ? + P keys.
Select the Destination Printer and Paper size in the Chrome Print Dialog on the left.
Select "Letter" Paper size for standard printers.
Select "1744907 4 in x 6 in" Paper size (or what you have named for the 4x6 option) for thermal label printers. Click the Print button at the top to print.