When does a taxpayer have to pay Estimated taxes?

I cannot answer that without knowing how much you owe because the answer depends on how much you owe on your current year’s tax return.  However, here are five general tips to help you decide if you should be paying Estimated Taxes. (1) If you have income from self-employment, alimony or other sources where taxes are not held out initially, then you probably need to pay estimated taxes.  (2)  Generally, you must pay estimated tax if you owe more than $1,000 after deducting tax withholding.  (3) The previous statement applies to all sole proprietors, partners, etc.  (4) You can use the worksheet in Form 1040-ES to calculate your estimated tax.  (5) Estimated taxes are paid 4 times per year: April 15, June 15, September 15 and January 15 of the following year.