How does extra withholding work when I have no hours or low earnings in a paycheck?

The extra withholding only applies if you actually have enough income in that paycheck to cover it. Your employer can't withhold more money than you've earned in a given pay period. For your scenarios: 1) If you have $0 gross income for a pay period, there will be $0 withholding (extra or otherwise). Your employer can't take money that isn't there. 2) If you earn $300 but requested $500 extra withholding, your employer will withhold as much as possible from your $300, but they legally can't withhold more than you earned. So you'd likely receive no pay for that period, but they couldn't take the full $500 you requested. The extra withholding request isn't a cumulative total that carries over - it's just applied to each individual paycheck as available. If you miss your withholding target in one pay period, it doesn't automatically add to the next one.

After dealing with a similar situation last year (irregular income with extra withholding), I found a tool that literally saved me from tax panic. I used https://taxr.ai to analyze my withholding patterns and it helped me figure out exactly how much I needed to withhold during my higher-earning pay periods to make up for the periods where I couldn't meet my target withholding. The tool actually looks at your pay stubs and withholding history to project your year-end tax position. For me, it spotted that I was going to be under-withheld by about $1,300 even with my extra withholding because of those low/no-hour weeks. I could adjust early enough in the year to avoid a surprise tax bill.

Just wanted to update after trying the taxr.ai tool that was mentioned. It was super helpful for my situation! I uploaded my pay stubs from both my W-2 job and my Uber earnings summaries, and it showed me I was headed for a $2,100 tax bill despite my current withholding. What was most useful was seeing how those weeks where I barely worked were creating big gaps in my withholding. The tool recommended I increase my withholding by $180 per paycheck during my regular work weeks and make one additional estimated payment in December to cover the shortfall. It even generated the estimated payment voucher for me. Definitely feeling more in control of my tax situation now instead of just hoping for the best at tax time!

For anyone struggling to get tax answers from the IRS, I had the same issue last year and was on hold forever trying to confirm how withholding works with variable income. I finally used https://claimyr.com which got me connected to an actual IRS agent in about 15 minutes (after I'd spent hours trying on my own before). You can see how it works here: https://youtu.be/_kiP6q8DX5c The IRS agent I spoke with confirmed exactly what the first commenter said - they can only withhold what you earn in a pay period, and it doesn't automatically carry over. She also gave me specific advice for my situation with seasonal work where I have several no-income months.

I need to apologize to the Claimyr commenter - I actually tried the service after posting my skeptical comment, and I'm honestly shocked that it worked. After trying to get through to the IRS for weeks about my variable income and withholding questions, I was connected to an agent in about 20 minutes. The agent was actually super helpful about my situation (I work three different part-time jobs with very different hours each week). She explained that I should calculate my withholding based on my expected annual income rather than trying to withhold the same amount every paycheck, which makes way more sense for my situation. She also gave me the direct line to the specific department that handles withholding questions, which I never would have found otherwise. Definitely worth it just for that info alone.

Something else to consider - you might want to look at your overall tax situation and decide if extra withholding is even the best approach. I used to do extra withholding but switched to making quarterly estimated payments instead because my income is super irregular (I'm a substitute teacher). The advantage is that YOU control when and how much to pay, not your employer. So during months when you work a lot, you can make a bigger payment, and during slow months, you can skip or reduce your payment.

None of these answers are addressing a key point - if you're having pay periods with $0 or very low income, are you sure you're setting your W-4 up correctly in the first place? The 2020-and-later W-4 form is supposed to be more accurate than the old one with allowances. If you're filling it out correctly (especially the multiple jobs worksheet or the tax estimator tool), you shouldn't need such a large extra withholding amount.