I am a single that works two jobs. I claim 0 across the board and I still owed taxes. SO I was told to withold extra from my paychecks? How do I know how much extra to withold from both state and federal? (I got fined by state last year for not taking enough out even though I claimed 0)
For the federal withholding use the IRS withholding estimator - https://www.irs.gov/payments/tax-withholding
Go to your state website as there should be a withholding calculator to use or access the state equivalent to the federal W-4 which will have worksheets to estimate your withholding allocations and additional state withholding.