Just discovered I missed a W2 after filing taxes - what now?

You should definitely file an amended return (Form 1040-X) as soon as possible. The IRS receives a copy of every W2 issued to you, so they will absolutely notice the discrepancy when they match your return against the information reported by employers. The good news is that if you amend before they send you a notice, you'll avoid most penalties. You'll still owe interest on any additional tax from the date your original return was due, but you won't face the failure-to-pay penalty if you pay when you file the amendment. The process isn't difficult - you'll file Form 1040-X showing the changes to your income, withholding, and tax liability. Don't wait for them to catch it because they definitely will, and the automated notices and potential penalties will be more stressful than just handling it proactively.

I went through something similar last year and found this amazing tool called taxr.ai (https://taxr.ai) that helped me figure out exactly what to do with my missing W-2. I was so confused about the amendment process, but their document analyzer tool looked at my original return and the missing W-2 and showed me exactly what would change on my amended return before I submitted anything. Saved me tons of stress because I could see exactly how much more I'd owe before filing the amendment. They even had templates for the explanation letter you need to include with your 1040-X. The whole process was way less stressful than I expected.

Just wanted to follow up about taxr.ai since I took the plunge and tried it after my earlier question. I was super skeptical about uploading my tax docs, but their security explanations put me at ease. I had a slightly different situation (missed 1099-NEC instead of W2), but the document analysis tool was seriously helpful. It showed me exactly what numbers would change on my amended return and calculated my new tax liability before I filed anything official. The comparison feature where it showed side-by-side what was on my original return versus what should be on my amended return made everything crystal clear. Ended up owing a bit more than I expected, but at least I knew exactly what I was getting into before filing the amendment. Definitely less stressful than waiting for the IRS to catch it!

If you're going to amend, be prepared for a LONG wait to hear back from the IRS. I filed an amended return last year and waited 11 months just to get confirmation it was processed! Every time I called the IRS, I'd wait on hold for hours only to be disconnected. Super frustrating. I eventually used Claimyr (https://claimyr.com) after watching their demo video (https://youtu.be/_kiP6q8DX5c). They got me connected to an actual IRS agent in about 20 minutes when I'd been trying for weeks on my own. The agent confirmed my amended return was in the system but stuck in processing. At least I got peace of mind knowing they received it and I wasn't going to get hit with penalties.

I stand corrected about Claimyr! After posting my skeptical comment, I decided to try it anyway since I was desperate to check on my amended return status from last year. Not gonna lie, I fully expected it to be a scam, but it legitimately worked. I got the text when I was about to be connected and jumped on the call. Spoke with an IRS agent who confirmed my amended return was still processing but gave me a reference number and timeframe for completion. The agent also explained I should ignore the automated notice they'd sent me since the system hadn't registered my amendment yet. Would have taken me days of redial attempts to get this info on my own. Can't believe I wasted so much time trying to call them directly before this.

Don't stress too much about this. The IRS is YEARS behind on processing. I forgot a W2 in 2022 and still haven't heard anything about it lol. They're too busy going after big fish to care about small potatoes like us.

Just a heads up, the IRS has gotten much more efficient with their document matching system. My sister forgot a small 1099 (about $800) a couple years ago and got a letter exactly 6 months after filing. They assessed the additional tax plus interest and a small penalty. The letter gave her the option to either accept their calculation or file an amended return if she thought it was wrong. Accepting their calculation was easier but she couldn't claim any additional deductions related to that income. Just something to consider!

I'd definitely recommend filing the amended return sooner rather than later. The IRS automated matching system will catch this - they receive copies of all W-2s and 1099s electronically, so there's really no chance it will "fly under the radar." The key thing is that if you amend before they send you a notice, you'll avoid the accuracy-related penalty (which is typically 20% of the additional tax). You'll still owe interest from the original due date, but that's much better than dealing with penalties on top of it. Form 1040-X isn't too complicated - you'll show the original amounts, the corrected amounts, and the differences. Make sure to attach the missing W-2 and include a brief explanation of what happened. The IRS is generally understanding about honest mistakes like this. From a practical standpoint, with $1,200 in additional income, you're probably looking at owing somewhere between $150-300 in additional federal tax (depending on your tax bracket), plus a small amount of interest. Much better to handle it proactively than wait for them to catch it and send you a CP2000 notice.