OK, I think I understand what you are saying.
I tried re-estimating using the TT interview to calculate estimated tax payments. I padded some numbers (just in case), and asked it to calculate 100% of my tax (instead of 90%).
It came up with an amount for all 4 payments = X
As mentioned in my earlier post, from our 3/31 paycheck, I calculated that the current federal tax withheld was not 35% of the current salary+RSUs. The difference in the amounts is Y. However, Y is only off by about $3k from the above TT estimate of X. (X+$3K = Y)
From what you are saying, in your above example, if I made quarterly payments of 4000, 4000, 5000, 5000 I would have had an underpayment penalty from Q1 and Q2. However, if I paid 5000, 5000, 4000, 4000, then I would not have any penalty, correct?
So it is to my advantage (if I can't estimate equal payments), to make higher payments in Q1 and Q2, and I can adjust lower as the year goes on, if I know I will be overpaying taxes.
And to avoid penalties, I should overestimate, rather than underestimate.
Am I right to assume that my calculation of this first quarter taxes (using salary+RSU) is correct? We did not have any capital gains this quarter. Do I need to add in any dividends or interest earned in this quarter as well, or can I assume the interest/dividends are added at the end of the year.
If the above is correct, can I use my calculation of Y as my quarterly estimated tax payment?
