Question: what is the difference between 0 and 1 on w4?
Answer: It won't create problems with the IRS, it will just determine how much you'll get back on your tax return next year. If you claim 0, you will get less back on paychecks and more back on your tax refund. If you claim 1, you will get more back on your paychecks and less back on your tax refund when you file next year.