The Surprise Bill Coming to Those Who Underpay Their Taxes

[Mark.b2]

5. I understandy why the IRS has the 90% rule, and I always intende to abide by it...

I just don't get why it's a thing.

If I, as a taxpayer, pay 100% of the taxes I owe for the year, I should be in the clear as long as I pay 100% of what I owe.

I can't possibly know my tax bill until I'm able to to do the final math.

There ought to be an incentive for remitting early. Conversely, there could be law that says you lose the privilege to pay after the year's over if you fail to do so, do it wrong , etc.

I know many Americans like remitting throughout the year, and they ought to be able to do so. But, taxpayers should also have the ability to do it as a lump sum at year-end.