The annualized income method is definitely more complex than the regular method.
Unfortunately, only you are the one who knows how much income and deductions apply to each month so you can compute each "period" on the 2210 annualized method worksheet.
The periods that IRS wants the annualized (AGI) income and then further down on the Schedule A1, the deductions (itemized or standard), SE Tax, withholding, etc. on, is as follows:
January - March 31
January - May 31
January - August 31
January - December 31
So once you have the amounts calculated for the first period, then add April and May to that for the 2nd period and then for the next period, add June, July and August amounts to that, and then for the last period, add September, October, November and December.
The easiest way is to write down each item of income and withholding and deductions for the year and then go through each one to determine if it was evenly throughout the year and if so allocate it that way on your scratch pad worksheet. If it was not, then you must manually calculate how much to allocate to each month. Then total each item per month (each income, each withholding, each deduction, etc.) and then calculate it for each of the "periods" IRS has set up in the worksheet.
Here is a link to the IRS Form 2210 so you can see how it is broken down:
IRS Form 2210
Here is a link to the IRS Instructions for Form 2210:
IRS Instructions for Form 2210 Regular and Annualized
[Edited 03/15/2021|12:04 pm pst]
