What is IRS Form 2210?

Form 2210 figures the penalty for paying too little estimated tax during the year. Tax software fills it in at the end of a return, and it is the form behind the notice when the IRS bills a penalty nobody expected. Most filers never send it. The ones who do are usually filing it to pay less than the IRS would charge on its own.

What the form does

The full name is Underpayment of Estimated Tax by Individuals, Estates, and Trusts. It compares what you owed by each of the four estimated tax due dates against what you had paid by then, and charges interest on each shortfall for every day it stayed unpaid. The total lands on line 19 and carries to Form 1040 line 38, where it adds to the balance due or comes out of the refund.

The flowchart at the top of page 1 sends most people away. Leave the form off your return and the IRS figures the penalty under the regular method and mails a bill. You file it only when one of the five boxes in Part II applies. Three of those boxes, B, C, and D, mean you compute the penalty yourself because your figure comes out lower than the one the IRS would reach.

Part I, the required annual payment

Part I produces the number the rest of the form turns on, the amount you were required to pay for the year. Line 1 is tax after credits from Form 1040 line 22. Line 2 adds other taxes, including self-employment tax, Additional Medicare Tax, and Net Investment Income Tax. Line 3 subtracts refundable credits such as the earned income credit and the additional child tax credit. Line 4 combines them into current year tax. If line 4 is under $1,000, stop. You owe no penalty and you do not file.

Line 5 is 90% of line 4. Line 6 is federal income tax withheld, with estimated payments left out. Line 7 is line 4 minus line 6, and under $1,000 it is the second exit. Line 8 is last year's total tax, or 110% of it when last year's AGI was over $150,000 ($75,000 married filing separately). If you filed no return for 2024, or that year ran less than 12 months, skip line 8 and carry line 5 down. Line 9, the required annual payment, is the smaller of line 5 and line 8. That is the safe harbor rule written as arithmetic.

Then the form asks whether line 9 is more than line 6. If withholding alone already covers the required annual payment, there is no penalty and no form to file, however large the balance due in April. Box E, below, is the one exception.

Part II, the five boxes

Part II is titled Reasons for Filing. If none of the five boxes applies, the form tells you not to file it.

• Box A. You want the entire penalty waived. Check the box, file page 1 only, and leave the penalty for the IRS to figure.
• Box B. You want part of the penalty waived. You figure the full penalty and the waiver amount yourself and file the whole form.
• Box C. Your income arrived unevenly and the annualized income installment method gives a lower penalty. This one needs Schedule AI.
• Box D. Your penalty is lower when withholding counts on the dates it was actually withheld instead of in four equal amounts. It helps when a January bonus or a job that ended in spring put most of the year's withholding early.
• Box E. You filed a joint return for 2024 or 2025 but not both, and line 8 is smaller than line 5. Line 8 came from a return with a different filing status, so the IRS wants page 1 even when you owe nothing.

The waiver behind boxes A and B has two grounds. You retired after reaching age 62, or became disabled, in 2024 or 2025, and the underpayment was due to reasonable cause and not willful neglect. Or the underpayment came from a casualty, disaster, or other unusual circumstance where the penalty would be inequitable. Attach a statement giving the reasons and the period you want waived, plus documentation. For retirement that means the retirement date and your age on it. For a casualty it means police and insurance reports.

Part III, the regular method

Part III has four columns, one for each installment due April 15, June 15, September 15, and January 15. Line 10 is the required installment, 25% of line 9 in every column unless box C is checked, in which case the figures come from Schedule AI line 27. Line 11 is the estimated tax paid and tax withheld for that period, with withholding split into four equal amounts unless box D is checked. If line 11 covers line 10 in all four columns, stop. There is no penalty.

Column (d) has a rule worth using. File the return and pay the balance by January 31 and that payment counts in column (d), so the January 15 installment carries no penalty.

Lines 12 through 18 run the money through the columns in order. An overpayment in one period carries forward to the next, and an underpayment stays open until a later payment covers it. Line 17 is the underpayment for the column and line 18 is the overpayment.

Section B is one line. The math sits in a worksheet in the instructions, which takes each underpayment, multiplies it by the days it went unpaid over 365, then by the underpayment rate. The rate was 7% in every period of 2025, so a $2,000 shortfall left unpaid for 180 days costs $69. The worksheet total is line 19 and goes to Form 1040 line 38.

Schedule AI, the part that lowers the number

Schedule AI is page 3 and the reason most people file Form 2210 by choice. Instead of a flat quarter at each due date, it sizes each installment to the income you had received by March 31, May 31, August 31, and December 31. Each period's income is annualized by 4, 2.4, 1.5, and 1, and the installments build to 22.5%, 45%, 67.5%, and 90% of the year's tax. A contractor paid mostly in the fourth quarter, or anyone who sold an asset in December, owed little in April, and the regular method still charges as if a full quarter was due. The details are in our guides to the annualized income method and to filling out Schedule AI.

If a notice already arrived

A CP30 notice means the IRS ran the regular method for you and took the penalty out of your refund or added it to your balance. That figure is not final. File Form 2210 for the year on the notice with box C or box D checked, or with box A or B and the statement, and the IRS recomputes the account. The steps and what to send are in how to lower an IRS underpayment penalty.

Sources: Form 2210 instructions · About Form 2210 · IRS underpayment penalty