as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
hired with w-9, will i owe estimated tax quarterly?
user
you must pay your taxes at the quarterly intervals. for most people the withholding done by their employer satisfies this requirement. however, if your income does not have any withholding (or sufficient), then you must file quarterly estimated tax payments.  note that if you have a second job that does withhold, then you can adjust your w4 to request further withholding there and possibly reduce the need for estimated payments.  estimated tax payments also come into play with large investment earnings. the amount that you need to prepay the irs is impacted by the safe harbor rule, which i am sure others will provide the exact details on.
assistant