Your employer should be providing you a tax form at time of hire and annually thereafter. On this form you can dictate how much you want taken off your paycheque for income taxes or confirm the default deductions. I have always chosen a higher amount to ensure I don't get a surprise come time to file my income tax return. I always then get money back. I recommend you doing the same when you get the form next time around. If your employer doesn't provide you with it, ask for it. I am unsure about rules in your country but in mine an employer is required to provide you with one.