Use a tape measure. Wrap the tape measure around the wrist on which you plan to wear your Cartier watch.
Download and print the Cartier Wrist Sizer. Before printing, make sure the "page scaling" option is set to "None" in the dialog box of your printer options. The Cartier Wrist Sizer must be printed on full-size standard letter paper. Follow the instructions and make a note of your wrist size.
Go to "Customization", check the relevant field and indicate whether you prefer a loose, exact or tight fit for your watch. Cartier specialists will adjust the strap according to your preferred fit and the specific features of the model.