There is no specific level of income at which income taxes are due quarterly. Rather, it depends on the manner in which you receive your income.Every taxpayer is required by law to prepay a pro-rata share of their tax each year by the four quarterly tax payment dates (the first non-holiday weekday on or after the 15th of April, June, September, and January). Most taxpayers will fully satisfy this requirement through employer withholding; the only people who therefore must use estimated tax payments are those who have significant income that is not in the form of wages or salary, and thus not subjected to employer withholding.If you receive income in the form of wages or salary, your employer is required to withhold taxes from your paycheck and transmit those withholdings to the IRS on a fairly specific schedule. Employers must withhold these taxes from every paycheck according to the calculations mandated by the IRS. As a result of this ongoing withholding process, most people have enough prepaid tax withheld from their paychecks to satisfy the quarterly prepayment requirement.However, if you end up owing more than $1000 in tax, after subtracting employer withholding and refundable credits, you must have paid estimated taxes by the required dates to ensure that, between estimated tax payments and employer withholding, you made sufficient prepayments toward your total tax obligation before the due date of that quarter to satisfy the legal requirement in that quarter. There is more than one way to compute how much tax must be prepaid in each quarter, and so determining what the minimum required to be paid for individuals with complex tax situations can be quite difficult.Note also that the rule is not that you owe the IRS more than $1000 at the end of your return. Rather, itu2019s u201cowe over $1000 more in tax than the sum of your withholdings and refundable creditsu201d. If your tax exceeds your withholdings by $1200, but you get a refund because you have $2023 in nonrefundable credits, you may be assessed a penalty. Do not include anticipated nonrefundable credits when figuring how much tax you must prepay.If you receive a significant amount of nonwage income, itu2019s probably in your best interest to retain a tax accountant to ensure that your income is properly accounted for and the appropriate quarterly estimated tax payments made at the proper time to avoid the risk of being assessed an underpayment penalty. If, however, most or all of your income is from a regular wage or salary, you can simply make sure your W-4 withholdings are sufficient to ensure that your employer withholdjngs are enough to cover your anticipated tax obligation.