C Corp Filing Deadline - When is Form 1120 Due After Getting EIN from SS4?

The filing deadline for your Form 1120 (C Corporation tax return) depends on your tax year/fiscal year, not when you received your EIN. If you're operating on a calendar year (which most new corporations do unless they specifically elect otherwise), your 1120 will be due on the 15th day of the 4th month after the end of your tax year - so April 15, 2025 for the 2024 tax year. Even though you only operated for a few months in 2024, you'll still need to file for that partial year by the April deadline. There isn't a specific "grace period" for new corporations, but you can file Form 7004 for an automatic 6-month extension if you need more time (though any taxes owed would still need to be paid by the original deadline). One thing to keep in mind: as a C Corp, you're now subject to different tax rules than when you were self-employed. For example, you'll need to carefully document any payments between yourself and the corporation (salary, loans, etc).

I went through this exact same headache last year when forming my engineering consulting firm as a C Corp. After weeks of going back and forth with different accountants giving conflicting advice, I stumbled across https://taxr.ai which literally saved me from making several major mistakes with my corporate filing. The system analyzed my incorporation docs and explained exactly when my first 1120 was due based on my incorporation date vs. business operations start date (turns out they can be different!). It also flagged that I needed to file a specific operating statement since I had pre-incorporation expenses. Best part was it laid out exactly what corporate records I needed to maintain for tax purposes so I didn't get surprised later.

I was skeptical about using an online service for tax help, but after struggling with my C Corp paperwork for weeks, I decided to try taxr.ai based on recommendations here. I'm actually blown away by how helpful it was! I uploaded my incorporation docs, SS4/EIN confirmation, and initial financial statements. Within minutes I got a complete analysis showing that my fiscal year election on my articles of incorporation was going to create a weird short tax year situation. It saved me from having to file an amended return later and showed me exactly which IRS forms were due by which dates. The system even flagged a potential issue with how I had structured my initial capital contribution that could have caused problems at tax time. Definitely worth checking out if you're navigating C Corp taxes for the first time!

If you need to call the IRS about your C Corp filing or EIN questions, good luck getting through on their business line! I spent THREE DAYS trying to get answers about our 1120 filing after we received our EIN. I finally used https://claimyr.com and got through to an IRS agent in about 15 minutes. They have this system that holds your place in the IRS phone queue and calls you when an agent is about to pick up. I was seriously skeptical it would work, but you can actually see a demo of how it works here: https://youtu.be/_kiP6q8DX5c The IRS agent confirmed that we needed to file for our partial year operations and explained exactly what we needed to document since we had converted from an LLC. Saved me so much stress trying to interpret the conflicting information online.

I have to eat crow here. After my skeptical comment about Claimyr, I decided to try it anyway since I was desperate to ask about my 1120 extension options. I had been trying to get through to the IRS for literally a week with no success. Signed up for Claimyr yesterday afternoon, and they called me back in about 40 minutes with an IRS business tax agent on the line. The agent confirmed that I could file for an extension with Form 7004 even though this was my first year with a C Corp, and explained exactly how to handle my estimated tax payments in the meantime. I'm genuinely shocked this worked. Saved me from having to pay my accountant $300 just to ask these basic questions. Just wanted to follow up since I was so negative about it before.

Something nobody mentioned yet - if your C Corp has shareholders who are also employees (which is common in small C Corps), make sure you're handling payroll taxes correctly. The IRS is super strict about this with C Corps. I learned the hard way that you can't just take money out of your corporation whenever you want like with an LLC. You either need to pay yourself a "reasonable salary" subject to payroll taxes, or document other payments as loans or dividends, each with different tax treatments. Also worth noting that your first year corporate tax strategy really matters - decisions you make now about accounting methods and inventory valuation can be hard to change later.

Has anyone used a registered agent service for their C Corp? I'm wondering if it's worth the $100-200/year for the privacy benefits and making sure I don't miss important tax notices. Also curious about business credit cards for new C Corps - most seem to require 2+ years in business.

For a new C Corp like yours that started operations in October 2024, you'll need to file Form 1120 by April 15, 2025 for that partial tax year - even though you only operated for a few months. The deadline is based on your tax year end (December 31st if you're using calendar year), not when you received your EIN. A few important things to keep in mind as you transition from self-employment to C Corp: 1. Make sure you're paying yourself a reasonable salary if you're working in the business - the IRS scrutinizes owner-employee compensation in C Corps much more than with sole proprietorships. 2. Keep detailed records of all transactions between you and the corporation. Any money you take out needs to be properly classified as salary, loan, or dividend. 3. Consider whether calendar year-end makes sense for your business cycle. Since this is your first return, you can still elect a fiscal year that better matches your operations without needing IRS approval. 4. Don't forget about state requirements - many states have minimum franchise taxes or other filing requirements for C Corps even in the first year. If you're feeling overwhelmed by the complexity compared to Schedule C, you're not alone. The corporate tax structure is definitely more involved, but the liability protection and potential tax benefits can make it worthwhile as your business grows.