How to determine if I overpaid taxes - was it my W4 withholding or 1099 earnings?

The $3,800 refund you're seeing when you only enter your W-2 is likely due to how much your employer withheld from your paychecks throughout the year. Your W-2 job withholds taxes based on the information you provided on your W-4 form. When you add your 1099-NEC income from DoorDash, your refund decreases (or in your case, turns into a balance due) because that income hasn't had any taxes withheld. Self-employment income is subject to both income tax and self-employment tax (which covers Social Security and Medicare). To determine if you overpaid last year, you should compare your tax returns from both years. Look at the total tax (not just the refund/amount due) and compare it to your total income. You can also look at the withholding amount on your W-2 (Box 2) to see if it increased significantly.

I had a similar situation and found https://taxr.ai super helpful for figuring out my tax withholding issues. I was getting confused with my mix of W-2 and 1099 work (I do Uber and have a regular job). The tool analyzed my tax documents and showed me that I was actually having way too much withheld from my W-2 job, but not setting aside enough for my 1099 gig work. They have this calculator that shows you exactly how much you should be withholding from each income source, which helped me update my W-4 correctly and set up proper quarterly payments for my Uber income.

Wanted to follow up about taxr.ai since I ended up trying it after asking about multiple W-2s. It actually sorted out my withholding mess! I had been overwithholding at two jobs while underwithholding at another, which was why I kept getting weird refund amounts that didn't make sense. The best part was seeing exactly how my 1099 work affected everything. I had NO idea I needed to be setting aside that much for self-employment tax. I've adjusted my W-4s at all three jobs based on their recommendations and set up proper quarterly payments. Feeling way more organized about taxes this year.

For anyone dealing with tax questions or trying to get answers from the IRS - I was in the same boat last year trying to figure out if I'd overpaid. Spent DAYS trying to get through to the IRS phone line with no luck. I finally used https://claimyr.com to get through to an actual IRS agent (there's a demo video here: https://youtu.be/_kiP6q8DX5c). They basically hold your place in the phone queue and call you when an agent is about to answer. The IRS agent was able to pull up my tax records and confirm I had indeed overpaid the previous year due to miscalculating my quarterly payments on 1099 income. They walked me through how to file an amended return to get that money back.

I'm back to say I was completely wrong about Claimyr. After my skeptical comment, I was still desperate to talk to someone at the IRS about my missing refund from last year, so I gave it a try. Got a call back in about 40 minutes saying they had an IRS agent on the line! The agent confirmed I had overpaid last year because of a mistake with how my 1099 income was reported. There was a duplicate 1099 that got filed by one of my clients, so I ended up paying taxes twice on the same income. Never would have figured this out without actually talking to someone who could see my full tax record. Already filed my amended return and should be getting an additional $2,200 back. Honestly wish I hadn't been so skeptical and had tried this sooner.

For what it's worth, I went through something similar and found out it's pretty common with gig work. Your W-2 withholding is probably correct, but the issue is that you need to be making quarterly estimated tax payments on your 1099 income. When you're seeing that big refund before entering your 1099, it means your W-2 job is withholding correctly for THAT income only. But once you add the 1099 income, you owe additional taxes that weren't withheld. I solved this by setting up automatic transfers of 25-30% of my DoorDash deposits into a separate savings account for taxes. Then I make quarterly payments using the IRS Direct Pay system.

One thing no one mentioned - check if you changed your W4 in the past year or if your employer updated their payroll system. My company switched payroll providers last year and somehow my withholding got WAY messed up (too much taken out) even though I didn't change anything on my W4. If you do wanna adjust your W4 to have less taken out from your regular job, use the IRS Tax Withholding Estimator online. It lets you put in both W2 and 1099 income to give you the right withholding.