If you don’t respond to an IRS audit, the agency finishes the audit without you: it calculates what it believes you owe from the information already in its hands, assesses the tax, adds penalties and interest, and then begins collecting through liens, wage garnishments, bank levies, and other tools. You lose the chance to challenge the numbers in Tax Court before paying, and the bill grows every month you stay silent. The good news is that even after missing every deadline, you still have options — they’re just harder and more expensive than simply answering the letters would have been.
The Notices Build Toward an Assessment
The IRS doesn’t skip to seizing anything. It works through a sequence of letters, each with its own deadline, usually 30 days. Early notices ask for your records or your agreement to proposed changes. A CP2000, for example, flags mismatches between your return and what employers, banks, and brokerages reported.1Internal Revenue Service. Topic No. 652, Notice of Underreported Income – CP2000 Technically it’s an automated matching notice rather than a formal audit letter, but ignoring it leads to the same place.
Each unanswered letter pushes you closer to a unilateral assessment, where the IRS decides your tax bill without your input. The further along that sequence you get, the fewer tools you have to push back.
The Notice of Deficiency Is the Deadline That Matters
After the preliminary notices run out, the IRS issues a Notice of Deficiency, often called a 90-day letter and sent as Letter 3219 or Notice CP3219N.2Internal Revenue Service. Understanding Your CP3219N Notice It states the exact amount the IRS says you owe and gives you 90 days — 150 if you’re outside the country — to petition the U.S. Tax Court.3Taxpayer Advocate Service. Letter 3219, Notice of Deficiency
Tax Court is the only forum where you can contest the proposed tax before paying it. Miss the 90 days and the IRS formally assesses the amount. After that, your choices narrow to paying in full and suing for a refund, or asking for an audit reconsideration. Both are harder than just filing the petition on time.
One trap worth knowing: the IRS only has to mail the Notice of Deficiency to your last known address by certified mail. If you moved and never updated the IRS, the notice may be legally valid even if you never saw it, and the 90-day clock runs anyway. Keep your address current by filing returns or by submitting Form 8822.2Internal Revenue Service. Understanding Your CP3219N Notice
What Gets Added to the Bill
Once the IRS assesses tax on its own calculations, penalties and interest start stacking. More than one penalty can apply at the same time.
Accuracy-Related Penalty
The most common audit penalty is 20% of the underpayment. It applies to negligence, disregard of the rules, or a substantial understatement of income tax — meaning an underpayment that exceeds the greater of 10% of the tax that should have been reported or $5,000 for individuals.4Office of the Law Revision Counsel. 26 U.S. Code 6662 – Imposition of Accuracy-Related Penalty on Underpayments
Failure-to-File and Failure-to-Pay
If the audit involves a return you never filed, the failure-to-file penalty runs at 5% of the unpaid tax per month, capped at 25%. The failure-to-pay penalty runs at 0.5% per month, also capped at 25%. When both apply in the same month, the failure-to-file portion is reduced by the failure-to-pay portion, so the combined rate for that month is 5%, not 5.5%.5Office of the Law Revision Counsel. 26 USC 6651 – Failure to File Tax Return or to Pay Tax
Civil Fraud
If the IRS concludes the underpayment was due to intentional deception rather than carelessness, the penalty is 75% of the portion attributable to fraud.6Office of the Law Revision Counsel. 26 USC 6663 – Imposition of Fraud Penalty The IRS has to prove fraud by clear and convincing evidence, and it can’t stack this penalty on top of the accuracy-related one for the same underpayment. Refusing to respond to audit inquiries doesn’t help your case.
Interest
Interest accrues daily on both the tax and the penalties, running from the original due date of the return. The rate is the federal short-term rate plus three percentage points, adjusted quarterly. For the first quarter of 2026 it is 7%.7Internal Revenue Service. Interest Rates Remain the Same for the First Quarter of 2026 There’s no cap. It compounds until the balance is paid.
How the IRS Collects
Once the assessment is final and still unpaid, the IRS moves into collection. Before seizing anything, it must send a Final Notice of Intent to Levy — Letter 1058 or Notice LT11 — giving you 30 days to respond.8Internal Revenue Service. Understanding Your LT11 Notice or Letter 10589Office of the Law Revision Counsel. 26 U.S. Code 6331 – Levy and Distraint
Federal Tax Liens
A federal tax lien is a legal claim against everything you own and anything you later acquire. It arises automatically when you don’t pay after the IRS demands payment.10Office of the Law Revision Counsel. 26 U.S. Code 6321 – Lien for Taxes When the IRS files a Notice of Federal Tax Lien in the public record, it tells creditors the government has first priority. That filing can damage your credit and make it very difficult to sell property, refinance a mortgage, or borrow.
Levies
A levy is the actual seizure. The IRS can garnish wages, drain bank accounts, intercept tax refunds, and take physical property including vehicles and real estate.9Office of the Law Revision Counsel. 26 U.S. Code 6331 – Levy and Distraint Wage levies are continuous, taking a chunk of each paycheck until the debt is resolved. Bank levies are a one-time freeze: the bank holds the funds for 21 days before sending them to the IRS.
Collection Due Process Hearing
The Final Notice of Intent to Levy also gives you the right to a Collection Due Process hearing by filing Form 12153. A timely CDP request pauses levy action while the hearing is pending and suspends the IRS’s 10-year collection clock. You can appeal the hearing decision to Tax Court. Miss the deadline and you can still ask for an “equivalent hearing,” but it won’t stop a levy and you lose the right to go to court afterward.11Internal Revenue Service. Form 12153, Request for a Collection Due Process or Equivalent Hearing
Your Passport Can Be Pulled
If your total federal tax debt — tax, penalties, and interest combined — exceeds $66,000 in 2026, the IRS can certify it as “seriously delinquent” to the State Department.12Internal Revenue Service. Revenue Procedure 2025-32 The State Department can then deny a new passport application, refuse a renewal, or revoke an existing passport. You’ll get a CP508C notice when the certification is made.13Internal Revenue Service. Understanding Your CP508C Notice The dollar threshold is adjusted annually for inflation.
Certification can only happen after the IRS has filed a lien and your administrative remedies have lapsed or run out. If you’re abroad when your passport is revoked, the State Department may issue a limited-validity passport to let you come home. The IRS reverses the certification within 30 days once the debt is resolved by payment, an installment agreement, an offer in compromise, or a hardship determination.
Criminal Charges Are Possible but Rare
Simply ignoring audit letters usually leads to civil penalties, not criminal charges. The IRS refers only a few thousand criminal cases a year. But if the agency concludes you willfully evaded tax — knew you owed and deliberately tried to avoid paying — tax evasion is a felony punishable by up to $100,000 in fines and five years in prison.14Office of the Law Revision Counsel. 26 USC 7201 – Attempt to Evade or Defeat Tax Willful failure to file is a misdemeanor carrying up to $25,000 in fines and a year in prison.15Office of the Law Revision Counsel. 26 USC 7203 – Willful Failure to File Return, Supply Information, or Pay Tax Patterns of hidden income, destroyed records, or false returns raise the risk considerably, and silence makes it harder to later argue that any errors were honest.
How Long the IRS Can Keep Coming
Two clocks matter, and both favor the IRS when you don’t respond. The agency generally has three years from the filing of a return to assess additional tax. If you never filed, there is no statute of limitations, and the IRS can assess at any time. Fraudulent returns also have no time limit.16Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection
After assessment, the IRS has 10 years to collect through levies or court proceedings.17Office of the Law Revision Counsel. 26 USC 6502 – Collection After Assessment That clock pauses in several situations, including a CDP hearing request, a pending offer in compromise, bankruptcy, or extended time outside the country. Don’t plan around the debt expiring; the IRS is skilled at tolling the period.
What You Can Still Do After the Assessment
Even if you’ve ignored every notice and the tax has been assessed, you still have paths forward. None are as good as responding on time, but they can cut what you owe or make it manageable.
Audit Reconsideration
If you never participated in the audit or never sent your records, you can request an audit reconsideration. No form is required: write to the IRS office that last contacted you, explain what you disagree with, and attach supporting documentation.18Taxpayer Advocate Service. Audit Reconsiderations Reconsideration is available when you have new information, dispute the amount, or didn’t take part the first time. You can’t use it if you signed a closing agreement, accepted an offer in compromise on the same liability, or a court has already ruled on the tax. If you already paid in full, use an amended return (Form 1040-X) instead.
Payment Plans
The IRS offers short-term plans of up to 180 days with no setup fee, and long-term installment agreements that spread payments over months or years with setup fees between $22 and $178 depending on how you apply.19Internal Revenue Service. Payment Plans; Installment Agreements Low-income taxpayers can get the setup fee waived. Penalties and interest keep running on a payment plan, but you avoid levy action.
Offer in Compromise
An offer in compromise settles the debt for less than the full balance. The IRS generally accepts the offer when it reflects the most the agency could reasonably expect to collect. You submit Form 656, a detailed financial statement, a $205 application fee, and an initial payment — 20% of the offer for a lump-sum option.20Internal Revenue Service. Offer in Compromise You must be current on all required filings and estimated payments. Low-income applicants can skip the fee and the initial payment.
Currently Not Collectible Status
If paying would create genuine financial hardship — monthly expenses exceeding income, or income limited to Social Security or similar benefits — you can ask the IRS to classify your account as currently not collectible. Expect to document your finances in detail. Active collection stops while the status is in place, but future refunds still get applied to the balance, and penalties and interest continue to accrue. If you owe more than $10,000, the IRS will usually file a federal tax lien as a condition of granting the status.
Innocent Spouse Relief
If the assessment stems from income, deductions, or credits attributable to your spouse or former spouse on a joint return, file Form 8857 to ask the IRS to hold only the responsible spouse liable for that portion. The deadline is generally two years after the IRS first tries to collect from you, with different rules for equitable relief. You can’t use this remedy if a court already ruled on the liability or you signed a closing agreement covering the same debt.21Internal Revenue Service. Instructions for Form 8857 – Request for Innocent Spouse Relief