Form 1120 Explained: U.S. Corporation Income Tax Return Guide for Small Business
What Form 1120 is, who files it, when it's due, and how to fill it out. Complete guide for small business owners.
Form 1120 is one of the forms every US small business eventually encounters. Here's everything you need to know.
What is Form 1120?
1120 — U.S. Corporation Income Tax Return
Purpose: C-Corp annual tax return
Filing deadline: April 15 (or 15th of 4th month after fiscal year-end)
Who must file Form 1120?
If you're a US-based business or self-employed individual, you likely need to file Form 1120 if any of these apply:
- You operate a C-Corporation
- You must file every year, even if the C-Corp had no income
How to complete Form 1120
The form can look intimidating, but the process breaks down into:
1. Collect the information (payee name, TIN, amount paid)
2. Fill out the form (paper or electronically)
3. Deliver copies (to recipient, IRS, and state if required)
4. Keep a copy for your records (7 years recommended)
Penalties for missing Form 1120
Penalties scale with how late you file:
- Up to 30 days late: $60 per form
- 31 days to August 1: $130 per form
- After August 1 or not at all: $330 per form
- Intentional disregard: $660+ per form
For a business with 10 unfiled forms, that's $6,600 in penalties — easily avoided by filing on time.
How TinSuite generates Form 1120
Instead of manually tracking, TinSuite auto-generates Form 1120 at year-end:
- Contractor/employee data auto-populates from your records
- Amounts are pulled from payments/payroll data
- Generated PDF is IRS-ready
- Electronic filing supported