What is Form 1040-ES?

Form 1040-ES is the IRS form used to calculate and pay quarterly estimated taxes for self-employed individuals and business owners. If you expect to owe $1,000 or more in taxes after subtracting withholding and credits, you must make quarterly payments. The form includes a worksheet to estimate your annual tax liability and divide it into four installments due in April, June, September, and January.

The quarterly payment calendar

Q1 covers January through March and is due April 15. Q2 covers April and May and is due June 15. Q3 covers June through August and is due September 15. Q4 covers September through December and is due January 15 of the following year. Miss a deadline, and penalties start accruing immediately. Set calendar reminders two weeks before each date.

Calculating your estimated payment

Start with last year's tax liability as your baseline. If income is consistent, divide by four. If income varies seasonally, use the annualized income installment method. Safe harbor rule: pay at least 100% of last year's tax (110% if AGI exceeded $150,000) to avoid underpayment penalties regardless of actual liability.