So in the example, $40K is the magic number (anticipated tax due for year), and where Q1 is $11K, then Q2 could be as low as $9K, since (apparently) the overage from Q1 applies to lower the penalty threshold in Q2, so long as the cumulative of Q1 & Q2 add up to 50% etc.
OK, so that kinda fits my own situation, I had a busy (well compensated) 2024, so I based Q1 on that TY24 tax, regardless of a slow Q1, I was confident that by Q2 I would be back gainfully employed and just keep with the 25% flow. However, now we are five months in and my income is shaping up to be less than half of last years, if things don't pickup. I'll still be down in any case, and my Q1 is more than enough to be over 50% of the years total obligation. I feel like I ought send just a token, like $100, just to have something to point to, with the explanation as shown above.
Now, never mind that Q2 is a cheat, since it only has 8 weeks and five days rather than the 13 weeks a full quarter would have. The math is
Q1: Jan15-Apr15 = 90 days;
Q2: Apr16-Jun15=60 days;
Q3: Jun16-Sep15=91 days;
Q4 : Sep16-Jan15=122 days.
So while Q1 and Q3 would properly be 25%, Q2 should be 17% (rounded) while Q4 should be the remaining 33%. If one's income is constant through the year, that's how it would prorate. A traditional W2 employee has an equal amount deducted from each regular paycheck, not disproportionately more in Q2. Just my $0.02.
