IRS Penalties

Accuracy-Related Penalty (IRS): What the 20% Penalty Means and How to Fight It in 2026

By Angeline Balsitis, EA · Reviewed by Melissa Ly, Chief Tax Officer · Published October 4, 2025 · Updated July 7, 2026 · Editorial Standards

You're retired, your income is mostly Social Security plus a few 1099s, and an IRS letter just proposed thousands in extra tax — then added a separate line labeled "accuracy-related penalty" that tacks 20% on top of whatever the tax turns out to be. That penalty line feels like an accusation of dishonesty. It isn't one — and it's far from final.

The accuracy-related penalty is one of the most contestable charges the IRS makes, because it's a percentage of a number that is itself often wrong. Fight the underlying tax successfully and the penalty shrinks or disappears with it. If you're not sure which line on your letter is the penalty, the image below shows what it looks like on the page and where to find the figure that drives it.

Why the IRS charged you an accuracy-related penalty

The accuracy-related penalty under IRC §6662 adds 20% to the portion of tax you underpaid because of negligence or a substantial understatement of income tax. It is not a late-filing or late-payment charge — it targets what was on the return, not when you filed or paid it.

For individuals, two triggers do almost all the work. Negligence or disregard of rules means the IRS believes you didn't make a reasonable attempt to report correctly — ignored 1099s, deductions with no records, positions with no plausible basis. Substantial understatement is pure arithmetic: the tax you reported was short by more than the greater of $5,000 or 10% of the correct tax. No carelessness required — the math alone can trigger it.

How the penalty reached you matters. Most people first see it as a proposed line on a CP2000 notice, where the IRS's automated underreporter system matched your return against 1099s and W-2s and calculated the penalty by computer. The rest see it on an exam report after an audit, where a human examiner asserted it — and for most examiner-asserted penalties, the law requires written supervisory approval, a technical requirement that occasionally becomes a defense.

Here is every version of the penalty and what triggers each rate:

Two boundaries keep this penalty in perspective. It is not the fraud penalty — the civil fraud penalty is 75% and requires proof of intent, and the IRS cannot charge both on the same portion of an underpayment. And if your case involves offshore accounts, the 40% prong overlaps with a separate set of exposures covered in our guide to an undisclosed foreign account IRS problem. For how this penalty compares to every other charge the IRS stacks on back taxes, see how much are IRS penalties on back taxes.

How much is the accuracy-related penalty? A worked example

The accuracy-related penalty is always 20% (or 40%) of the underpayment — so the fastest way to cut the penalty is to cut the underpayment it's calculated on. A hypothetical shows why that matters so much.

Say you're retired, living on Social Security and an inherited brokerage account. Two years ago you sold the inherited stock. The broker's 1099-B reported the gross proceeds but no cost basis, so the IRS's matching system treated the entire sale as taxable gain and mailed you a CP2000 proposing $61,200 in additional tax.

The penalty math on that proposal:

• Proposed additional tax: $61,200
• Substantial understatement test: $61,200 exceeds both $5,000 and 10% of the correct tax — the penalty applies automatically
• Accuracy-related penalty: 20% × $61,200 = $12,240
• Plus interest on the tax and the penalty, running from the return's original due date

Now the fix. Inherited assets get a stepped-up basis to date-of-death value. Say you document that basis and the true gain produces only $4,800 of additional tax. The underpayment drops from $61,200 to $4,800 — and because $4,800 is under the $5,000 threshold, the substantial-understatement prong fails entirely. A good-faith basis error on inherited stock, backed by records, is also a weak negligence case. One well-documented response can turn a $12,240 penalty into $0, and roughly $73,000 of proposed debt into under $5,000.

To see how penalties and interest compound on your own numbers before you respond, you can estimate the total with our Penalty & Interest Calculator.

What happens if you ignore the penalty notice

An ignored accuracy-related penalty stops being a proposal and becomes an assessed debt that enters the IRS collection machine. The sequence is automated, and each stage removes an option you have today:

1. The response window closes. The date on your CP2000 or exam report passes with no reply, and the IRS treats its proposed figures — tax plus 20% penalty — as unchallenged. If you disagree with the underlying numbers, the CP2000 disagree playbook works only inside this window.
2. Notice of Deficiency. The IRS mails a CP3219A notice of deficiency — your last chance to contest the tax and penalty in Tax Court, within 90 days, without paying first.
3. Assessment. The 90 days pass, and the tax, the penalty, and interest all post to your account as legally owed. Interest on the penalty is backdated to the return's original due date, so the balance is already larger than the notice suggested.
4. The collection sequence begins. A CP14 bill arrives, followed by reminder notices, then a CP504 (the IRS can seize your state refund), then an LT11 final notice — after which, 30 days later, wage garnishment and bank levies become legal. If Social Security is your income, up to 15% of it can be levied through the Federal Payment Levy Program.

In 2026 there's a practical wrinkle: IRS staffing is down roughly 27%, which makes disputing a penalty by phone slower than ever — but the automated systems that assess penalties and issue levies never slowed down. Delay costs you options; it never costs the IRS anything.

Staring at a proposed 20% penalty right now?

Send us the notice before the response date printed on it passes. An experienced tax professional will check whether the underlying tax is even right, whether the penalty legally applies, and what your strongest removal argument is — free, confidential, no pressure.

Get My Free Case Review Call (888) 825-7779

How to get the IRS accuracy-related penalty removed: your options

Every path to removing the accuracy-related penalty runs through one of two arguments: the underlying tax is wrong, or you acted with reasonable cause and good faith. Which procedure you use depends on where you are in the timeline — and one popular shortcut is off the table. First-time abatement does not apply to the accuracy-related penalty. The first time penalty abatement waiver — and the Automatic Exemption from Penalty (AEP) replacing it starting summer 2026 — covers late-filing, late-payment, and deposit penalties, not §6662. A spotless compliance history helps your credibility, but it isn't a ticket by itself.

Before assessment is where cases are won. Answer the CP2000 or exam report with documents that correct the underlying tax, and contest the penalty in the same letter — both on the math (does the understatement still clear the $5,000/10% bar after your corrections?) and on the conduct (reasonable cause). If the examiner won't budge, take the free Appeals conference before the deficiency notice issues.

After assessment, the tools shift. A written reasonable cause penalty abatement request is the workhorse — it must tell a specific, documented story: you relied on a professional you fully informed, you reasonably didn't know an inherited asset's basis rules, a serious illness disrupted your recordkeeping. A well-built IRS penalty abatement letter leads with facts and proof, not apologies. If the exam happened without you — you moved, were hospitalized, never got the mail — audit reconsideration can reopen the whole adjustment, penalty included. And if abatement is denied, paying and filing a refund claim keeps the fight alive; our Form 843 instructions walk through that route.

One more defense worth knowing: for return positions with real legal support, "substantial authority" defeats the substantial-understatement prong, and a position disclosed on Form 8275 with a reasonable basis is protected from it too. These are mostly planning tools, but if your preparer took a defensible position, they belong in your response.

If some balance survives, resolve it before collection escalates — payment plans start at IRS.gov/payments, and if you're on a fixed income where any payment would be a genuine hardship, read our guide to IRS hardship social security status before agreeing to a payment you can't sustain.

How to respond to an accuracy-related penalty, step by step

1. Find the response deadline. The date printed near the top of your CP2000, exam report, or Notice of Deficiency controls whether you can still contest the penalty before it is assessed — calendar it today.
2. Verify the underlying adjustment. Pull the return for that year plus the records behind the disputed item — basis statements, 1099s, closing documents — and check whether the IRS's proposed tax is actually right.
3. Dispute the tax and the penalty together. Every dollar you knock off the proposed tax removes 20 cents of penalty automatically, so send corrections and documentation for the adjustment in the same response that contests the penalty.
4. Make a written reasonable-cause case. In the same response, explain the specific facts showing good faith — what records you kept, what advice you relied on, why the error was honest — and attach proof.
5. Resolve whatever balance survives. If tax or penalty remains after your dispute, set up a payment arrangement or hardship status before the balance enters the collection notice sequence.

When you can handle this yourself — and when help changes the outcome

You can usually handle an accuracy-related penalty alone when the fix is documentary and the dollars are small. A CP2000 that missed one 1099 you agree with, a basis figure you can prove with a single brokerage statement, a proposed penalty of a few hundred dollars — those are letter-and-enclosures problems. Write clearly, attach the proof, mail it certified, keep copies. The Taxpayer Advocate Service can also help free of charge if the IRS mishandles your response or a delay is causing hardship.

Experienced help changes outcomes in four situations. First, a Notice of Deficiency has already been issued — the 90-day Tax Court clock is unforgiving, and a missed petition converts a contestable proposal into assessed debt. Second, the proposed penalty is large (five figures), because the reasonable-cause narrative has to be built to the IRS's own standards, not just told sincerely. Third, multiple years or multiple issues are in play, where the order you resolve things changes the total. Fourth, the exam report uses fraud language or a 40% rate — that's a different weight class entirely. An honest rule of thumb: if losing the argument costs more than a year of your discretionary income, get a professional review before you respond, not after.

Terms on your notice, decoded

• Underpayment — the difference between the tax you should have paid and what your return showed; the penalty is always a percentage of this number.
• Negligence — failing to make a reasonable attempt to follow the tax rules or keep adequate records; carelessness, not dishonesty.
• Substantial understatement — an understatement exceeding the greater of $5,000 or 10% of the correct tax for an individual; triggers the 20% penalty on math alone.
• Reasonable cause and good faith — the §6664(c) defense: you made an honest, documented effort to report correctly, so the penalty shouldn't apply.
• Substantial authority / adequate disclosure — legal support for a return position, or disclosure of it on Form 8275, either of which can defeat the substantial-understatement prong.
• Supervisory approval — the §6751(b) requirement that a manager approve most examiner-asserted penalties in writing; computer-calculated CP2000 penalties are treated as exempt, but exam penalties without approval can sometimes be invalidated.

The IRS's own summary of the penalty, its triggers, and its relief standards is at IRS.gov: Accuracy-related penalty.

Accuracy-related penalty questions, answered

Your next 24 hours

1. Find two things on your notice: the line labeled "accuracy-related penalty" (note the amount) and the response date printed near the top — that date decides whether you can still fight this before it's assessed.
2. Gather your proof: the notice itself, your tax return for that year, and the records behind the disputed item — basis or inheritance documents, 1099s, and any correspondence with your preparer.
3. Get a free case review before your response window closes: call (888) 825-7779 or use the 2-minute form at claritytaxrelief.com/#consult. We'll tell you whether the underlying tax is even correct, whether the penalty legally applies, and which removal path fits your facts.

This guide is general information, not tax or legal advice for your specific situation. Eligibility for IRS programs depends on individual facts and circumstances; no outcome is guaranteed.

Related: how much are IRS penalties on back taxes · IRS civil fraud penalty · CP2000 notice · reasonable cause penalty abatement — or browse all guides.