Oh my, I'm sorry you had such a large bill. It's an unpleasant surprise. The best way forward is to make sure you don't have this happen again.
Of course I'm not sure but I'm guessing you haven't worked two jobs for more than a year? The reason I say this is many people with multiple employers tend to get caught by an unexpected balance due. This also happens to spouses where one earns less than the other. This also happens when someone stops a job and starts a new job. What's going on here?
When you look at the withholding tables (circular E), they arrive at an income tax bracket for you based on your likely standard deduction (and when they were still in play - your exemption). They calculate your estimated annual income based on that weekly, bi-weekly or monthly paycheck. The withholding table for just one of these employers cannot predict what your income will be at the other job or any other sources of income. It only calculates withholding for your one job. When you work a second or third job, your income tax bracket changes from 10% or 12% up to 22% or higher but the one employer withholds as if you are still in the lower tax bracket. This is why, when working more than one job, you need to withhold extra from both jobs.
Based on your circumstances, if you did owe $8K federally, you can withhold an extra dollar amount from each job per month of $1,000. We only have four months left in this year so that would make up $8K. Or you can make the recommended estimated tax payment for this year. But for 2025, I would highly recommend adjusting your W4 withholdings if you continue to work for two or more employers.
Cheers
