Suboxone strips shouldn't be cut by a patient. Your doctor should be the only one to cut a suboxone strip to make sure you get the correct dosage. Otherwise, you might get too less or too much Suboxone or damage the drug in the process.
I heard you can measure it with a ruler, but I also know you shouldn't mess with it yourself. Your doctor should do it for you. You really don't need us to help you do something that you might do wrong anyway.