IRS tax bill wrong? How to check and dispute it

Anthony's first reaction to the $57,000 was to believe it.

That is worth sitting with for a second. He had not filed for three years. He knew he had been paid roughly $70,000 a year as a contract network engineer, on 1099s, and he knew he had sent the IRS nothing. So when a stack of notices arrived saying he owed $57,000 in tax, penalties, and interest across those three years, it felt like a bill he had earned. He was ashamed. He was also, in a way that shame makes possible, relieved. A number is better than a fog. He started thinking about how to pay it.

He was about to pay roughly $35,000 more than he owed.

This chapter has one job, which is to make a habit permanent: before you decide how to pay a tax debt, decide whether it is correct. That is the Examine step, and it is not optional. The IRS is a large system that processes hundreds of millions of documents a year with a workforce that shrank by a quarter in 2025. It gets things wrong. More to the point, some of its most common procedures are designed to produce a number that is wrong in the IRS's favor, on the theory that you will show up and correct it. If you never show up, the wrong number becomes your debt.

The six ways the number is usually wrong

In my experience of reading accounts, incorrect balances come from a short list of causes. Here they are, roughly in order of how much money they involve.

The IRS filed the return for you. This is Anthony's situation, and it is the single largest source of inflated balances among people who owe. When you do not file and the IRS has income documents showing you were paid, it can eventually prepare a Substitute for Return under section 6020(b) of the Code. It uses every 1099 and W-2 it has, counts all of it as taxable income, allows no business expenses, no itemized deductions, no credits, no dependents, and files you as single or married filing separately regardless of your actual situation. Then it mails you a proposed assessment, waits, mails you a statutory notice of deficiency generally giving you 90 days from mailing to petition the Tax Court, or 150 days if the notice is addressed to a person outside the United States, waits again, and assesses. The result is a legal debt computed on the worst assumptions about you that the paperwork allows.

Anthony's substitute returns treated his full $70,000 of 1099 income as profit. His actual profit, after equipment, software licenses, mileage to client sites, a home office, and health insurance premiums, was closer to $46,000 a year. His actual tax, including self-employment tax, was about $9,000 a year rather than the $14,000 the IRS assessed. The failure-to-file penalty, 25 percent, had been computed on the inflated tax. So had the interest. Three years of that gap, with penalties and interest stacked on it, was the $35,000.

It is worth understanding what kind of document a substitute return is, because people treat it as a finding and it is nothing of the sort. It is generated by an automated program from the information returns in the IRS's possession, with no human judgment applied to whether a single working adult with 1099 income is likely to have had expenses. The program is not trying to compute your tax. It is trying to produce a number large enough that you will show up and correct it, and if you do not, the number stands, because the law lets it. Of all the documents the civil side of the IRS produces, the substitute return is the only one deliberately designed to be wrong. Knowing that should change how you feel about replacing it: you are not arguing with the IRS. You are supplying the information it never had.

The IRS changed your return and you did not answer. The Automated Underreporter program matches the income on your return against the W-2s and 1099s on file. When they do not match, you get a CP2000, which proposes additional tax, usually with a 20 percent accuracy penalty. If you do not respond, the proposal becomes an assessment. The CP2000 is often right. It is also often wrong in ways that are easy to show: a 1099 for a stock sale where the IRS counted the full proceeds as gain because the broker did not report your cost; a 1099-R for a rollover that was never taxable; a 1099-NEC for income you did report, just on a different line; a form issued to you by mistake. Audits produce the same kind of error when the taxpayer did not show up with records.

A payment was lost or misapplied. You paid, and the account does not show it. This happens with checks that posted to the wrong year, payments made under a spouse's Social Security number, estimated payments the IRS applied to a different period than you intended, and electronic payments that failed silently. The fix is documentary: a bank record showing the payment, matched against the account transcript showing where it went.

A penalty does not fit the facts. The IRS assesses penalties by formula and removes them by request. A failure-to-file penalty on a return you filed on time, with proof. An estimated tax penalty where you qualified for a safe harbor. An accuracy penalty on a position you had a reasonable basis for. We spend Chapter 12 on penalty relief, but the first question is whether the penalty should have been there at all.

The math is wrong or the IRS used the wrong data. Math-error notices, incorrectly transcribed figures, a 1099 that belongs to someone with a similar name, identity theft where a stranger filed under your number. Less common than the others. Not rare.

The clock ran out. If the ten-year collection period has expired on a balance, the debt is not collectible, period, and any balance still showing on the account should be zero. The IRS is supposed to catch this automatically. It does not always. Chapter 7.

The tool you need is the transcript

Every one of these shows up in the account transcript you pulled in Chapter 4, which is why I had you pull it before anything else.

A substitute return shows as a transaction code 150 with a very small or zero amount and a later code 290 or 300 for the assessment, usually accompanied by a 971 notice code describing a substitute for return. A CP2000 assessment shows as a 290 with the accuracy penalty right behind it as a code 240. A lost payment shows as an absence: your bank statement says $2,000 left on March 14, and there is no 670 on the transcript for that date. A penalty you can dispute shows as a 166, 276, or 240 you can point to.

Lay your transcript next to your own records for each year. Three columns: what you believe happened, what the transcript says happened, and where they differ. The differences are your case.

How to fix each one

I will take them in the same order.

Replacing a substitute return. The remedy is almost absurdly simple in concept: file the real return. You prepare an accurate return for that year, with your actual filing status, dependents, deductions, and business expenses, sign it, and send it to the IRS address designated for returns being filed after a substitute return assessment. In practice the IRS processes this as an audit reconsideration. A person compares your return to the substitute, and if your figures are supported, adjusts the assessment to match. The penalties and interest are recomputed on the corrected tax.

A few practical points. You need records, or reasonable reconstructions of records, for the expenses you claim. Bank statements, credit card statements, invoices, and mileage logs are what the IRS wants to see. If the year is old and the records are thin, you can reconstruct using what you have, but be prepared to defend the numbers. Send the return by certified mail. Expect it to take months. If the IRS has already started levying on the substitute assessment, you can usually get collection paused while the reconsideration is open by asking for a hold and documenting that the return has been filed. And file all three years, or however many there are, at once, because a partial fix leaves you noncompliant and blocks every option in Part III.

Anthony filed three returns in one envelope, with a cover letter listing each year and stating that the returns were being submitted to replace substitute-for-return assessments. His records were a mess, but his bank and card statements were complete, and he had kept client contracts that showed travel requirements. Eleven weeks later his combined balance was adjusted from about $57,000 to about $23,000. He still owed $23,000. He was in a position to deal with $23,000.

Reopening a CP2000 or audit assessment. This is also an audit reconsideration. You write a letter to the address on your notice, or to the campus that issued the assessment, explaining which items you dispute and why, and you attach the documents that show it: the brokerage statement with your cost basis, the rollover confirmation, the corrected 1099. Form 12661 is the IRS's optional cover form for this and it helps route the request. The standard is that you are presenting information the IRS did not consider when it assessed, so the letter should say what is new and why it changes the result. If the IRS agrees, the tax comes down, the penalty computed on it comes down, and the interest on both comes down. If it does not, you can take the dispute to Appeals.

One limit matters here. A notice of deficiency has a strict Tax Court filing period: generally 90 days from mailing, or 150 days if addressed to a person outside the United States. Use the last filing date on the notice and current court instructions; continuing to correspond with the IRS or asking for audit reconsideration does not extend it. Petition the Court, not the IRS. If the date may have passed, seek individual advice immediately rather than assuming either that an extension is available or that every possible remedy is gone. Audit reconsideration is a discretionary administrative process, not a replacement for preserving the court deadline. Refund procedures and doubt-as-to-liability offers have their own eligibility limits. See Tax Court guidance for starting a case.

Finding a lost payment. Pull the bank record showing the payment cleared. Call the IRS with the date, amount, and the account it was drawn on. If the payment posted to the wrong year or the wrong taxpayer, they can usually trace it and move it on the phone or with a short written request. If it never posted at all, you may need to send a copy of the canceled check or the electronic confirmation. Once the payment is credited to the correct period, the IRS recomputes penalties and interest from the date it was actually received, not the date it was found.

Disputing a penalty. For a penalty that should never have applied, as opposed to one you want forgiven, the remedy is a written request for abatement with the proof: the certified mail receipt showing the return was timely, the prior-year return showing you met the estimated tax safe harbor, the documentation of the position you took. Form 843 is the general-purpose form for penalty and interest abatement claims. Chapter 12 covers the broader relief programs.

Correcting a math error or bad data. Math-error notices give you sixty days to disagree, and if you do, the IRS has to reverse the assessment and go through normal deficiency procedures. Identity theft is handled through Form 14039 and the IRS's identity theft unit, which was carrying a backlog of hundreds of thousands of cases at the end of 2025 with resolution times running over a year and a half. Start early.

Dealing with an expired debt. If your own CSED calculation says a year has expired and the account still shows a balance, call and ask for the IRS's CSED for that period. If they agree it has passed, the balance is written off. If they do not agree, ask for the computation and compare it to yours. Chapter 7 will teach you to make the calculation.

Doubt as to liability

Most people who have heard of an Offer in Compromise think of it as the program for people who cannot pay. That is one kind. There is a second kind, made on a separate form, Form 656-L, called an offer based on doubt as to liability. It says, in effect, "I do not think I owe this, here is why, and I am offering to settle the dispute for this amount." There is no application fee. There is no financial statement. The question is purely whether the assessment is correct.

It is a narrower tool than it sounds. You cannot use it for a liability a court has already decided, or for a year where you had the chance to go to Tax Court and the issue is one you could have raised there. But for a disputed CP2000 assessment, a penalty the IRS will not abate, or an audit result you believe is wrong on the merits, it is a formal channel with a formal answer, and the IRS has to consider it.

Sarah's version of "wrong"

Sarah's $42,000 was not wrong in the way Anthony's was. The audit of her joint returns had been correct. Her husband had earned the money and not reported it. The tax was properly computed and properly assessed against both of them.

What was wrong, in a different sense, was the idea that she should pay it.

The Code has a specific remedy for a spouse who signed a joint return without knowing about the understatement, and Chapter 13 is where we take it up in full. I mention it here because it shows the same question from a different angle. "Is the number right" has two parts: is the tax correctly computed, and is it correctly attributed to you. Anthony's problem was the first. Sarah's was the second. Both of them were about to pay a debt that, properly examined, was not theirs in the amount stated.

What this step is worth

I am aware this chapter is less dramatic than a levy. It involves reading transcripts and mailing envelopes. But I will put the economics in front of you plainly.

Anthony spent about forty hours gathering records and preparing three returns, plus a few hundred dollars for a preparer to review them. The result was a $34,000 reduction in what he owed. There is no payment plan, no offer, and no penalty-relief program in Part III that would have produced that result for him, because every one of those programs starts from the number on the account. The only thing that changes the number on the account is proving it wrong.

For most readers the answer to "is the IRS wrong" will be no, or not by much. Jennifer's transcript matched her return to the dollar. That is fine. The hour it took to check was the cheapest hour in her whole case. For the minority whose answer is yes, this is the most valuable chapter in the book, and it had to come before the payment options, because once you have agreed to a number in writing, it gets much harder to argue it later.

Next, the question of time. Every month between the day you read this and the day you resolve the debt has a price, and it is not just interest. Chapter 6 is about what waiting actually costs, how the IRS applies the money you do send, and the two or three situations where waiting is the right move.