Estimated tax · Updated November 6, 2026

IRS underpayment penalty calculator for 2026 (Form 2210)

If you did not pay enough tax during 2026 through withholding and quarterly estimated payments, the IRS charges a penalty that works like interest on each late or short payment. Enter your numbers to see what it comes to, the way Form 2210 figures it.

Estimate my penalty

Calculate your 2026 underpayment penalty

2026 total taxExpected tax for 2026, after credits$2025 total taxFrom your 2025 return$

2025 AGI was over $150,000$75,000 if married filing separately. Then the prior-year safe harbor is 110%.2026 federal tax withheldW-2, 1099 and other withholding for the year$

Estimated payments made

Amount and the date you actually paid. Leave $0 for payments you skipped.

Rest of the tax paid on

Estimated 2026 underpayment penalty

$174

Required for 2026: $12,000, or $3,000 each quarter

Installment due	Short by	Penalty
April 15, 2026	$0	$0.00
June 15, 2026	$0	$0.00
Sept. 15, 2026	$3,000	$121.97
Jan. 15, 2027	$3,000	$51.78

Form 2210 regular method, with withholding treated as paid evenly on the four due dates. Rates: 6% to June 30, 2026, then 7%; the rate for January to April 15, 2027 is not announced yet, so 7% is assumed. Estimate, not tax advice.

How the penalty is figured

Find the required annual payment: the smaller of 90% of your 2026 tax or 100% of your 2025 tax (110% if your 2025 adjusted gross income was over $150,000, or $75,000 married filing separately).
Divide it into four equal installments, due April 15, June 15 and September 15, 2026 and January 15, 2027.
Count your withholding as paid one-fourth on each due date, and estimated payments on the dates you made them.
Apply each payment to the earliest installment still short.
Charge each shortfall at the IRS underpayment rate for the days it stays unpaid, up to the date you pay or April 15, 2027, whichever comes first.

There is no penalty if your 2026 tax minus withholding is under $1,000, or if you owed no tax for 2025, filed a full-year 2025 return and were a US citizen or resident all year.

Example: two payments skipped

Last year’s tax was $12,000 and this year’s will be $14,000, so the required payment is $12,000 (100% of last year’s tax is less than 90% of this year’s), or $3,000 a quarter. The first two payments are made on time; the September and January payments are skipped, and everything else is paid on April 15, 2027. The September shortfall costs $121.97 and the January one $51.78, a penalty of about $174.

How to avoid it, even late in the year

Withhold more. Withholding counts as paid evenly through the year even if it comes out of your last paychecks, so raising it on your W-4 in the fall can cover earlier quarters. An estimated payment only counts from the day you make it.
Use last year’s tax. Paying 100% (or 110%) of last year’s tax in four equal parts on time avoids the penalty even if this year’s income is much higher.
Uneven income? If most of your income came late in the year, the annualized income method (Schedule AI of Form 2210) can lower or remove the penalty for the early quarters.
Skip January 15 by filing your 2026 return and paying everything by February 1, 2027.

Do you have to file Form 2210?

Usually not. If none of the boxes in Part II of Form 2210 applies, the IRS figures the penalty itself and sends a bill. You file it only to ask for a waiver (box A or B), to use the annualized income method (box C) or to treat withholding as paid when it was actually withheld (box D). A waiver is possible for a casualty, disaster or other unusual circumstance, or if you retired after age 62 or became disabled during the year or the year before and the underpayment had reasonable cause. Otherwise, the IRS says the penalty generally cannot be waived for reasonable cause.

Questions

How is the IRS underpayment penalty calculated?

Like interest. Each quarterly installment you underpaid is charged at the IRS underpayment rate for every day it stays unpaid, from its due date until you pay it or April 15 of the next year, whichever is earlier. For 2026 the rate is 6% through June 30 and 7% after.

How do I avoid the estimated tax penalty?

Pay, through withholding and estimated payments, at least the smaller of 90% of this year’s tax or 100% of last year’s (110% if last year’s AGI was over $150,000), in four equal parts on time. Or owe less than $1,000 after withholding.

Do I have to file Form 2210?

Usually not. The IRS figures the penalty and sends a bill. You file Form 2210 only to claim a waiver, to use the annualized income method for uneven income, or to treat withholding as paid on the actual dates.

Can the underpayment penalty be waived?

Sometimes: for a casualty, disaster or other unusual circumstance where the penalty would be inequitable, or if you retired after age 62 or became disabled and the underpayment had reasonable cause. It is generally not waived for reasonable cause alone.

Is the penalty for 2026 the same rate all year?

No. It is 6% from April 16 to June 30, 2026 and 7% from July 1 through December 31, 2026. The IRS has not yet announced the rate for January to April 15, 2027; this calculator assumes 7%.

Self-employed and behind on estimated taxes?

We work out what you owe for 2026, what to pay before January 15 and how to set up 2027 so it does not happen again. Tax planning assessment $195, in person in Naperville, IL, by phone or by Zoom.

Tax planning

Where these rules come from

USTAXX prepares tax returns and offers tax planning. We are not a CPA firm and do not represent clients before the IRS. This page is general information, not tax advice for your situation.