Corporate Estimated Tax Guide
An interactive tool to help your corporation plan payments, manage cash flow, and avoid underpayment penalties based on Form 1120-W.
Key Thresholds & Rules at a Glance
$500
Corporations must pay estimated tax if they expect their tax liability to be this amount or more.
4
The number of required installment payments per tax year.
$1M
The taxable income threshold that defines a "Large Corporation," which has special rules.
100%
Pay 100% of your prior or current year's tax to meet the "Safe Harbor" and avoid penalties.
Payment Method Simulators
Your corporation's income pattern determines the best way to calculate your estimated tax installments. Explore the methods below to find the most cash-flow friendly option for your business.
Safe Harbor Calculator
This is the simplest way to avoid penalties. Your required annual payment is the smaller of 100% of your current year's tax or 100% of your prior year's tax. Use the calculator to see your required installments.
Annualized Income Method Simulator
Ideal for businesses with fluctuating or back-loaded income. This method lets you base your payments on income earned to date, rather than a fixed quarterly amount. This can significantly improve cash flow. See how your payments change based on when you earn income.
Adjusted Seasonal Method Eligibility Checker
Perfect for businesses with predictable busy seasons (e.g., retail, tourism). If you qualify, you can pay the bulk of your estimated tax during your high-income months. Check your eligibility below.
To qualify, your taxable income for the same 6-month period must be, on average, 70% or more of your total annual income for the last 3 years.
Year 1 (Prior)
Year 2 (Prior)
Year 3 (Prior)
Other Key Provisions
🗓️ Find Your Due Dates
Enter your fiscal year end date to see your estimated tax payment deadlines for that tax year.
💰 Quick Refund for Overpayments
If you overpay your estimated tax, you don't have to wait for your annual tax return to get a refund. You can file Form 4466 for a quick refund if your overpayment is:
- ✓ At least 10% of your expected tax liability, AND
- ✓ At least $500.