# Estimated tax penalty: why you were charged and how to lower it

Source: https://backtaxesdesk.com/penalties-interest/estimated-tax-penalty
Publisher: Back Taxes Desk (backtaxesdesk.com), independent editorial site
Topic: Penalties and Interest
Last updated: 2026-09-19

> The estimated tax penalty is an IRS charge for not paying enough tax through withholding or quarterly payments during the year. You generally avoid it if you owe less than $1,000 when you file, or if you paid at least 90% of this year's tax or 100% of last year's (110% if last year's AGI was over $150,000).

## Key facts

- No penalty if balance due is: Under $1,000
- Safe harbor: 90% of current-year tax or 100% of prior-year tax, whichever is less
- Higher-income safe harbor: 110% of prior-year tax if prior-year AGI was over $150,000
- Rate used: IRS underpayment rate: 7% for all of July to December 2026
- Form used: Form 2210, with Schedule AI for uneven income
- Tax year 2026 due dates: April 15, June 15 and Sept. 15, 2026; Jan. 15, 2027

## What is the estimated tax penalty?

The estimated tax penalty, which the IRS formally calls the underpayment of estimated tax by individuals penalty, is charged when the tax you paid during the year through paycheck withholding and quarterly estimated payments fell short of what you owed at each due date. It is not a late filing or late payment penalty. You can file on time, pay your full balance in April and still owe it.

The IRS treats income tax as a pay-as-you-go tax. Each quarter has its own installment due date, so the penalty is figured quarter by quarter, based on how much was short, for how long, and at the IRS underpayment interest rate for those days (IRS, Underpayment of estimated tax by individuals penalty).

| Income earned | Payment due |
| --- | --- |
| January 1 to March 31, 2026 | April 15, 2026 |
| April 1 to May 31, 2026 | June 15, 2026 |
| June 1 to August 31, 2026 | September 15, 2026 |
| September 1 to December 31, 2026 | January 15, 2027 |

Estimated tax installment due dates for tax year 2026

A payment due on a weekend or legal holiday is on time if made the next business day. None of the four tax year 2026 dates falls on a weekend.

## Why did I get an underpayment penalty?

Most people get an underpayment penalty because income arrived without tax taken out of it. Common triggers are freelance or gig income, a large capital gain, a retirement account withdrawal with little withholding, rental income, or a side business that grew during the year.

- **New self-employment.** No employer withholds tax, and nobody reminds you that April 15 is also the first quarterly deadline.
- **A one-time windfall.** Selling stock or property in spring means that quarter's installment was due by June 15, not next April.
- **Paying everything at year end.** A single payment in January covers only the last installment; earlier quarters stay underpaid for months.
- **Too little withholding on a W-4.** A second job or a working spouse can push you into a higher bracket than either paycheck assumes.

If the IRS figured the charge, you will usually see it on Notice CP30, which says a penalty was added because estimated payments were missing or late. It can also show up as a line on your return if your software calculated it.

## How do I avoid the estimated tax penalty? The safe harbor tests

You avoid the estimated tax penalty if you meet any one of the IRS safe harbor tests. The tests look at what you paid on time, not at your final balance alone.

### Worked example: the prior-year safe harbor

Say your 2025 return showed total tax of $12,000 and your 2025 AGI was $90,000. In 2026 your freelance business takes off and your 2026 tax turns out to be $20,000. The required annual payment is the smaller of 90% of $20,000 ($18,000) or 100% of $12,000 ($12,000). Paying $3,000 by each of the four due dates avoids the penalty, even though you still owe $8,000 in April.

If your 2025 AGI had been over $150,000 ($75,000 if married filing separately), the prior-year figure becomes 110%, so you would need $13,200, or $3,300 per installment.

> **Withholding counts as paid evenly:** Federal tax withheld from wages is treated as paid in four equal parts on the due dates unless you show otherwise. Raising withholding in November can therefore cover shortfalls from earlier quarters, something a late estimated payment cannot do.

## How much is the IRS penalty for underpayment?

The IRS penalty for underpayment works like interest: the shortfall for each installment is multiplied by the underpayment rate for the number of days it stayed unpaid. The individual underpayment rate is 7% for July through September 2026 and 7% for October through December 2026 (IRS, Quarterly interest rates).

Example: if your June 15 installment was $2,000 short and you paid it 91 days later, the charge is about $2,000 x 7% x 91 / 365, or roughly $35. The count for that installment stops on the day the shortfall is paid, so an early catch-up payment directly shrinks the charge. Rate changes are tracked on our [IRS interest rate 2027](https://backtaxesdesk.com/penalties-interest/irs-interest-rate-2027) page, and the method behind them on [how IRS underpayment interest is set](https://backtaxesdesk.com/penalties-interest/irs-underpayment-interest-rate).

## Can the estimated tax penalty be waived?

Yes, but only on narrow grounds. The IRS may waive the estimated tax penalty in two situations, and each needs a written request.

1. **Casualty, disaster or other unusual circumstance.** A fire, flood or similar event made paying on time impossible and charging the penalty would be inequitable. Attach supporting documents such as insurance or police reports.
2. **Retirement or disability.** You or your spouse retired after reaching age 62, or became disabled, in the tax year or the year before, and the underpayment was due to reasonable cause rather than willful neglect. Include the retirement date and age, or the date of disability.

> **The usual relief routes do not apply:** The general [reasonable cause penalty abatement](https://backtaxesdesk.com/penalties-interest/reasonable-cause-penalty-abatement) rules do not cover the estimated tax penalty, and [first time penalty abatement](https://backtaxesdesk.com/penalties-interest/first-time-penalty-abatement) covers only failure-to-file, failure-to-pay and failure-to-deposit penalties. The new automatic relief starting with 2027 due dates covers those same three penalties, not this one.

## Is Form 2210 required? Using it to dispute or lower the penalty

Form 2210 is not required for most people. If none of the special boxes applies, the IRS figures any penalty and mails a bill. You must attach Form 2210, Underpayment of Estimated Tax by Individuals, Estates, and Trusts, when you want one of these results:

| Box | What it does | When it helps |
| --- | --- | --- |
| A | Requests a waiver of all of the penalty | Retirement after 62, disability, casualty or disaster |
| B | Requests a waiver of part of the penalty | The same grounds, but only some quarters were affected |
| C | Uses the annualized income method (Schedule AI) | Most income arrived late in the year |
| D | Treats withholding as paid on the actual dates | Most withholding happened early in the year |
| E | Other required filing | For example, a joint return in one year but not the other |

Form 2210 Part II boxes that change the result

Schedule AI is the tool for uneven income. A consultant who earned most of the year's fees in December would owe little for the April, June and September installments under the annualized method, because the required payment follows when the income was actually earned.

Farmers and fishermen who earn at least two-thirds of gross income from that work follow separate rules: pay the full tax by March 1, or make one estimated payment by January 15.

## What to do if you already owe the underpayment penalty

1. Check the math against your own records of payment dates. A missed payment the IRS never credited is a correction, not a waiver.
2. If income was uneven or withholding came early, file or send Form 2210 with Schedule AI or box D checked.
3. If you qualify for a waiver, send a signed statement made under penalty of perjury to the address on the notice.
4. Pay the rest by the date on the notice to stop interest on the penalty itself, which starts from the notice date. If you cannot pay at once, a [short-term payment plan](https://backtaxesdesk.com/payment-plans/irs-short-term-payment-plan) gives up to 180 days.
5. Adjust your 2027 plan: raise withholding or schedule quarterly payments so the same thing does not happen next year.

For how this penalty fits alongside the late filing and late payment charges, see the [IRS penalties guide](https://backtaxesdesk.com/penalties-interest).

## Common questions

### Why do I owe an underpayment penalty if I paid in full in April?

Because the estimated tax penalty measures whether enough tax was paid by each quarterly due date during the year. Paying the whole balance in April stops it growing but does not erase the earlier shortfalls.

### Does the IRS waive the estimated tax penalty for first-time offenders?

No. First Time Abate does not cover the estimated tax penalty. The only waivers are for casualty, disaster or unusual circumstances, and for people who retired after 62 or became disabled with reasonable cause.

### Do I have to file Form 2210 myself?

Usually not. If you are not requesting a waiver, using the annualized income method or treating withholding as paid on actual dates, the IRS figures any penalty and sends a bill.

### What IRS notice is sent for the estimated tax penalty?

The IRS usually sends Notice CP30, which says a penalty was charged because estimated payments were not made or were late. It shows the amount and the date to pay, and mentions the retirement and disability waiver.

### What rate does the IRS use for the estimated tax penalty in 2026?

It uses the individual underpayment rate for each period. That rate was 7% for January to March 2026, 6% for April to June, and 7% for July through December 2026.

## Sources

- [Underpayment of estimated tax by individuals penalty](https://www.irs.gov/payments/underpayment-of-estimated-tax-by-individuals-penalty)
- [Instructions for Form 2210](https://www.irs.gov/instructions/i2210)
- [Quarterly interest rates](https://www.irs.gov/payments/quarterly-interest-rates)
- [Understanding your CP30 notice](https://www.irs.gov/individuals/understanding-your-cp30-notice)
- [Estimated tax FAQs for individuals](https://www.irs.gov/faqs/estimated-tax/individuals/individuals-2)