since you may have no idea of what your 2025 federal and sate income taxes will be the IRSand usually the staes offer a safe harbor.
have enough withheld to equal or exceed 100% of your 2024 tax which should be known if you've filed. That jumps to 110% for federal if your adjusted gross income for 2024 was $150,000 or more (1/2 that if married filing separately) this is merely to avoid penalties for not prepaying enough of your 2025 taxes. you could still have a substantial amount due at filing time. some taxpayers do not like owing a lot come 4/15. if you are one of them then increase the amount withheld if possible.
withholding has an advantage over estimated tax payments. despite the period actually withheld 1/4 of the total is, by default, deemed paid each installment period whereas estimates only count for the period in which made.
