They don’t need to know that, though. For instance, the irs could send you a statement with everything they know and a total at the bottom. You can either pay

They don’t need to know that, though. For instance, the irs could send you a statement with everything they know and a total at the bottom. You can either pay that, or if you think you should pay less, prove it by filling out a bunch of 1040/1099/etc forms with supporting evidence. Frankly, I’d love it. If it’s close enough, I think many people would pay a bit more just to eliminate the hassle.