How Far Back Can the IRS Audit?

The common answer is three years, but it is not an absolute maximum. The general federal assessment period is usually three years after the return was due or filed, whichever is later. A six-year period can apply to specified substantial omissions, including reporting 25 percent or less of the gross income that should have been reported. There is no assessment time limit for a false or fraudulent return filed with intent to evade tax or when a required valid return was not voluntarily filed. Agreements, litigation, certain international information, and other statutory events can also extend or suspend the period. The audit selection window and the legal assessment deadline are related but not identical questions.

This guide is part of Steady’s Business Taxes & the IRS library. It explains the federal workflow in practical terms, but the correct result still depends on the payment year, entity, worker relationship, filing method, and state rules.

The answer in context

Three years is the general assessment period

A timely return filed before its due date is generally treated as filed on the due date for this purpose.

Late returns generally start later

The period commonly runs from the IRS receipt date when a valid return is filed after the due date.

Substantial omissions can produce six years

Topic 305 describes a six-year period when unreported income exceeds 25 percent of gross income shown, with another rule for specified foreign financial asset income.

No valid return can mean no running clock

An IRS substitute return does not generally start the taxpayer’s three-year assessment period.

Fraud can remove the limit

A false or fraudulent return filed with intent to evade tax can be assessed without the ordinary time limit.

A taxpayer can agree to an extension

The IRS may request a written consent; the taxpayer can review, negotiate, or decline it, understanding the examination consequences.

The period can be suspended

A notice of deficiency, litigation, bankruptcy, and other statutory events can affect the expiration date.

Record retention follows more than one rule

Employment taxes, property basis, loss carryovers, refund claims, and state law can require records beyond three years.

Step-by-step workflow

1. Identify the exact return. Record taxpayer, form, tax period, original due date, extension, actual filing date, and acceptance evidence.
2. Confirm whether a valid return was filed. Do not assume a draft, rejected e-file, substitute return, or payment started the normal period.
3. Calculate the general date. Start with the later of the applicable due date or filing date under the current rule.
4. Test six-year exceptions. Review gross-income omissions, foreign financial assets, and the exact statutory language for the return.
5. Test unlimited-period exceptions. Consider nonfiling and fraud only from actual facts and qualified legal analysis, not suspicion.
6. Review extensions and suspensions. Locate Forms 872, deficiency notices, court cases, bankruptcy, and other events affecting the date.
7. Check special assets and claims. Maintain property basis, carryovers, bad debts, worthless securities, employment-tax, and refund support for their own periods.
8. Compare state law. State audit and assessment periods may differ from federal rules.
9. Document the conclusion. Prepare a return-by-return retention and statute schedule with sources and reviewer.

Worked example

A calendar-year business timely files its 2022 return in 2023. The general federal assessment period may expire three years after the applicable filing date, but the business does not destroy all source records on that date. It first checks whether there was a substantial omission, a signed extension, an open examination, property basis carried into later years, employment-tax records, or a longer state period. The conclusion is documented by return rather than guessed from the calendar year alone.

The example is intentionally a workflow illustration, not a conclusion for every taxpayer. A strong file connects each number on the return to a source report and records why an exception, exclusion, or classification was applied.

Records to keep

Keep the source form or worksheet, contracts or engagement records, payer and recipient identity support, the detailed payment or payroll ledger, bank and processor reconciliation, calculations, correspondence about corrections, filed copies, recipient-delivery evidence, and federal and state acceptance confirmations. Store the records by tax year and keep superseded versions when they explain a correction.

A reviewer should be able to begin with the final reported amount and trace it back to transactions without rebuilding the year. Add a short review memo for judgments such as worker status, corporate exemption, payment-method exclusion, state filing, or unusual timing. That memo is often more useful than another unlabeled spreadsheet.

Common mistakes

• Calling three years a guaranteed cap. Exceptions, extensions, and suspensions can change the date.
• Counting from the tax year-end. The filing due date and actual filing date matter.
• Treating a rejected e-file as filed. Retain acceptance evidence.
• Destroying property records after three years. Basis can remain material until disposition and the later return’s period expires.
• Ignoring state statutes. Each jurisdiction can use a different period.
• Signing an extension automatically. Review the scope and consequences.
• Confusing audit with collection. The assessment period and the collection period answer different questions.

Final review before filing

Confirm the form and revision year, taxpayer identities, dollar fields, payment categories, withholding, filing channel, recipient statement, state obligations, due dates, and approval. Compare the final output with the source reconciliation rather than reviewing the form in isolation. If software recalculates an amount after an edit, rerun the tie-out.

Keep preparation, filing, and acceptance as three separate statuses. A draft can be complete but unfiled; a transmission can be sent but rejected; a federal return can be accepted while a state return is still missing. This status discipline prevents a polished PDF from being mistaken for finished compliance work.

How to handle a discrepancy

When a source form, ledger, payroll report, or software preview disagrees with another record, stop before filing and identify which amount represents the underlying transactions. Trace the difference by vendor or employee, date, invoice or payroll run, payment channel, and account. Common causes include a payment posted to the wrong year, a void recorded after a report was generated, a card payment included with checks, a duplicate import, an incorrect taxpayer name, or a late adjustment. Record the explanation and the correcting entry or form request.

Do not erase the trail by overwriting the original report. Save the first version, the reconciliation, the corrected version, and the approval. If a third party supplied an incorrect information return, request a formal correction and retain the correspondence. If a return was already transmitted, use the current correction procedure for that form and channel. A corrected recipient copy without a corresponding agency correction can leave the records inconsistent.

Federal filing is only one layer

Federal acceptance does not settle state or local obligations. A state may use a different threshold, worker test, filing portal, account number, transmittal, or due date. Some states receive eligible information through a combined program, while others require a direct submission. Verify the jurisdictions connected with the payer, recipient, employee, work location, withholding, and business activity. Save state confirmations separately so they are not hidden behind the federal acceptance.

Make next year easier

Turn the year-end work into a monthly control. Collect identity forms during onboarding, code payment methods consistently, reconcile payroll and vendor activity each month, and flag vendors or income streams that need special treatment. Schedule a fall review of missing forms, classification questions, state registrations, and electronic-filing access. By year-end, the team should be validating a maintained file instead of reconstructing twelve months of transactions under a deadline.

Practical implementation notes

Return statute schedule

Track form, period, due date, filed date, acceptance, general date, exceptions, and reviewer.

Permanent records

Keep entity, ownership, elections, basis, asset, and carryover records as long as relevant.

Consent log

Retain every extension request, signed form, scope, date, and advice.

Hold notice

Suspend routine destruction for any audit, notice, claim, appeal, or litigation.

For the next layer of context, see this related guide, the companion reporting article, and the connected workflow.

If the form, books, and filing status do not agree, Steady can help reconcile the source data and prepare a clean filing package through its specialist service.