You need Schedule AI to compute your required installments of estimated tax if you will be using the "annualized income installment method", which lets you defer payments of estimated tax if your income fluctuates during the year.
For each column enter your total income for the period shown, minus your adjustments to income. Don't forget to deduct half of your self-employment tax for each period. You can compute the correct amount by completing Part II of Schedule AI of this form and multiplying the amount on lines 34a to 34d by 8, 4.8, 3 and 2, respectively.
If your annualized income is over $166,800 ($83,400 if married filing separately), your itemized deductions need to be reduced in accordance with the IRS instructions to take into account the phaseout of itemized deductions for high-income taxpayers.
We do this computation for you. For details, see the Line 6 Itemized Deduction Worksheet in the IRS Instructions for Form 2210, Schedule AI.
We enter $3,650 times the number of personal exemptions to which you are entitled.
We calculate the tax using the Tax Table, Tax Rate Schedules, or Capital Gain Tax Worksheet, as appropriate. If this return is for a child under age 23, please use Form 8615 and override our computation.
If you had self-employment income, complete Part II now and enter the amounts from lines 34a to 34d. On a joint return, add together the amounts for you and your spouse.