Does that paycheck count as last year’s income or the new one?
Just asking out of curiosity, I’m not trying to dodge taxes or anything.
The IRS generally treats personal income on a cash basis. That means it doesn’t matter when you earned the money, it matters when you get the check. You may also want to see how your employer reports the income on your W-2.
(Business accounting works on an accrual basis, where you count income when you earn it, regardless of when you actually get paid.)
Most of the above is true but assuming you are an employee and receive a W-2 you definitely need to go by the W-2 and your employer should calculate it on the cash basis.
Even if you aren’t an employee and receive a 1099, the company should use the cash basis.
Many small businesses also use the cash basis for all of their accounting. Larger businesses are required to use the accrual basis.
Thanks for the elaboration. I should have added that IANAA.