Internal Revenue Code 6001: Recordkeeping, Retention, and the Cohan Rule

Internal Revenue Code Section 6001 recordkeeping requirements are the federal rules that make every taxpayer keep books and source documents complete enough for the IRS to verify each figure on a return. The statute is short; the regulations, publications, and case law layered on top of it reach into every dollar of income, every deduction, and every asset you own. Falling short doesn’t just cost you a deduction in an audit — it can trigger penalties of 20% to 75% of the resulting underpayment.

The Standard IRC 6001 Sets

Section 6001 directs every person liable for federal tax to keep records, render statements, and follow whatever rules the Treasury Secretary prescribes.¹ The regulation that fills in the detail, 26 CFR 1.6001-1, requires “permanent books of account or records, including inventories, as are sufficient to establish the amount of gross income, deductions, credits, or other matters required to be shown” on a return.²

The IRS doesn’t mandate a particular system. A spreadsheet, accounting software, or a paper ledger all work, as long as the records are complete enough to trace every line on your return back to a source document.³ What counts as “sufficient” depends on what you’re documenting. A wage earner’s records look different from a landlord’s, and both look different from a business owner’s. The common thread: objective proof of the amount, date, and character of each item.

Income Documentation

For most people, income records start with the information returns payers send each January — W-2s for wages, 1099-NEC for contractor pay, 1099-K for payment platforms, 1099-INT for interest, 1099-DIV for dividends, and so on.⁴ Those forms alone don’t satisfy Section 6001. You should also keep bank and brokerage statements that reconcile to the totals on your return.

The reconciliation matters because the IRS routinely runs a bank-deposit analysis to look for unreported income: it totals your deposits, subtracts identifiable non-income items like transfers and loan proceeds, and treats what’s left as taxable.⁵ If a $10,000 deposit was a gift or a repaid personal loan, you need a contemporaneous record — a note in the check memo, a loan agreement, a written statement from the sender — to keep the IRS from treating it as income.

Business Expenses

For general business expenses, keep the original invoice or receipt, proof of payment such as a canceled check or credit card statement, and enough context to show the expense was ordinary and necessary. A credit card charge to “Office Supplies Inc.” is a starting point; the invoice showing what was actually purchased is what ties the expense to the business.³ If you keep a general ledger, entries should trace back to those source documents. Gaps in that chain are where deductions get disallowed.

Travel, Meals, and Gifts Under Section 274(d)

Travel, meals, and gifts sit under a stricter rule than ordinary expenses. IRC Section 274(d) requires you to document four specific elements for each expense: the amount of each separate expenditure, the time (dates of departure and return, business days spent), the place (destination city or locality), and the business purpose or expected benefit.⁶ Record them at or near the time of the expense. A log written from memory months later carries far less weight.

Documentary evidence rules are also tighter. You need a receipt for any lodging expense regardless of amount, and for all other travel expenses when the cost is $75 or more, with a narrow exception for transportation charges where receipts aren’t readily available.⁷ A hotel receipt should show the property, location, dates, and separate charges for lodging, meals, and incidentals.

This is where most travel deductions collapse. People keep the credit card statement but not the hotel folio. They remember the trip was for business but never wrote down who they met or why. The Cohan rule described below can occasionally rescue a partial deduction elsewhere; Section 274(d) expenses are specifically excluded from it. If you don’t have the required records, the deduction is gone.

Property Basis and Depreciation

Basis records are among the most important to maintain, and the easiest to lose track of. Your basis in property is what you paid for it, adjusted upward for improvements and downward for depreciation and certain credits.⁸ That adjusted basis determines your taxable gain when you sell.

For real estate, keep the original closing statement, documentation of every capital improvement (roof replacement, kitchen remodel, added square footage), and a year-by-year record of any depreciation claimed if the property was used for business or rental. Sales tax, legal fees, and recording fees paid at purchase also add to basis.⁸ For stocks and mutual funds, brokerage statements and purchase confirmations establish cost basis. Each reinvested dividend is a separate purchase with its own basis; losing track of those reinvestments means overpaying tax on sale.

Home Office Records

If you claim the home office deduction, you need records proving two things: exclusive and regular use of a specific area as your principal place of business (or as the place where you meet clients in the normal course of business), and the actual expenses allocable to that space.⁹

Publication 587 calls for documentation identifying the business part of the home, evidence supporting exclusive-and-regular use, and records of the depreciation and expenses allocated to that portion.¹⁰ In practice: a floor plan or measurements showing square footage of the office relative to the whole home, plus utility bills, insurance records, repair receipts, and mortgage interest statements. A photo of the dedicated workspace helps. It’s hard to argue exclusive use for a desk in the corner of the playroom.

If you use the actual expense method rather than the simplified method, you also need to track the home’s depreciable basis for as long as you own the property.¹⁰

Charitable Contributions

Charitable substantiation is layered, and the thresholds are lower than most people expect.

For any cash contribution — any amount at all — you need a bank record (canceled check, bank statement, credit card statement) or a written receipt from the charity showing its name, the date, and the amount.¹¹ Dropping $20 in the collection plate with no record means no deduction.

For contributions of $250 or more, you must have a contemporaneous written acknowledgment from the charity, obtained by the date you file the return (or its due date including extensions). The acknowledgment must state the cash amount, describe any non-cash property given, and indicate whether the charity provided goods or services in return, with a good-faith estimate of their value.¹²

Non-cash donations over $500 require Form 8283, Section A. When the claimed value exceeds $5,000, you complete Section B and obtain a qualified appraisal from an independent appraiser.¹³ Skipping the appraisal is an automatic disallowance, no matter how obviously the item was worth $10,000.

Employment Tax Records

If you have employees, Section 6001 reaches your payroll records too, and the retention period is longer than the general standard. Employers must keep employment tax records for at least four years after the tax becomes due or is paid, whichever is later.¹⁴ That covers W-4s from each employee, wages paid, dates of employment, tip reports, and copies of Forms 941 or 944.

Worker classification deserves separate attention. If you treat someone as an independent contractor, keep records showing why. The IRS weighs three categories: behavioral control (whether you direct how the work is done), financial control (who provides tools, whether expenses are reimbursed, how the worker is paid), and the type of relationship (written contracts, benefits, permanence).¹⁵ A misclassification caught years later brings back payroll taxes, penalties, and interest. A written analysis prepared at the time of hiring is your strongest defense.

Electronic Records

You don’t have to keep paper originals. Scanned receipts, digital invoices, and cloud-based accounting all work, provided the system meets Revenue Procedure 97-22. The core requirements come down to reliability, accessibility, and an audit trail:

Reasonable safeguards to prevent unauthorized creation, alteration, or deletion of records.
Regular evaluations, including periodic checks, to confirm stored records haven’t deteriorated or been corrupted.
An indexing system that lets you locate and retrieve specific documents.
The ability to produce legible hard copies on request.
Cross-referencing that connects general ledger entries to underlying source documents.

¹⁶

One detail that catches people off guard: if you switch accounting software or stop maintaining the hardware needed to read your old files, the IRS treats those records as destroyed. Before migrating, confirm you can still produce everything from the old system in a readable format, or convert it into the new system with the audit trail intact.¹⁶

How Long to Keep Records

Keep records until the statute of limitations runs on the return they support. The specific periods depend on the situation:

Three years is the standard. The IRS generally has three years from the date you filed (or the due date, if you filed early) to assess additional tax.¹⁷
Four years for employment tax records, measured from when the tax was due or paid, whichever is later.¹⁴
Six years if you omit income exceeding 25% of the gross income reported on your return. The same extended period applies if omitted income exceeds $5,000 and is tied to foreign financial assets reportable under Section 6038D.¹⁷
Seven years if you file a claim for a refund based on worthless securities or a bad-debt deduction.¹⁸
Indefinitely if you file a fraudulent return or don’t file at all. There is no statute of limitations in those cases.¹⁸

Property basis records sit in a category of their own. Keep them until the statute of limitations expires on the return reporting the sale, which means holding onto purchase and improvement documents for the entire time you own the asset plus at least three more years after you sell.¹⁸ For a home you own for 25 years, that can mean retaining records for nearly three decades.

The Cohan Rule and Its Limits

If you know you spent money on a legitimate business expense but lost the receipt, all is not necessarily lost. The Cohan rule, from a 1930 federal appeals court decision, lets courts estimate a deduction when a taxpayer can prove an expense was incurred but can’t nail down the exact amount. The court said absolute certainty in such matters is usually impossible, but any estimate should “bear heavily” against the taxpayer whose lack of records is their own fault.¹⁹

The rule has real limits. You still have to prove the expense actually happened, through testimony, bank records, partial documentation, or other evidence. A vague claim of “probably around $5,000 on supplies” with nothing behind it won’t trigger Cohan relief. And critically, the rule does not apply to expenses under Section 274(d) — travel, meals, gifts, and listed property. Congress specifically overrode Cohan for those categories through the strict substantiation rules above. Lose your travel log, and no court will estimate the deduction for you.

What Happens When Records Fall Short

When records don’t hold up in an audit, the consequences cascade. The IRS can reconstruct your income using indirect methods like the bank-deposit analysis or comparisons to similar taxpayers in your industry. You then carry the burden of proving the reconstruction wrong, which is an uphill fight without the documents that should have existed.

The most immediate hit is disallowance. Without substantiation, a claimed business expense gets reclassified as a non-deductible personal expenditure, which raises your taxable income. That increased income becomes the base for penalties.

The accuracy-related penalty under Section 6662 adds 20% to any underpayment caused by negligence or a substantial understatement.²⁰ Negligence includes the failure to keep adequate books and records, so poor recordkeeping is essentially a direct trigger.²¹

In fraud cases, the stakes jump. Section 6663 imposes a penalty equal to 75% of the portion of the underpayment attributable to fraud.²² The line between sloppy records and fraud is drawn on patterns: consistently destroying records, keeping two sets of books, or repeatedly failing to report known income can push a negligence case into fraud territory. At that point the statute of limitations disappears, and combined tax, interest, and penalties can exceed the original unreported amount many times over.

1
Office of the Law Revision Counsel. 26 U.S. Code 6001 – Notice or Regulations Requiring Records, Statements, and Special Returns
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eCFR. 26 CFR 1.6001-1 – Records
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Internal Revenue Service. Recordkeeping
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Internal Revenue Service. Gather Your Documents
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Internal Revenue Service. 9.5.9 Methods of Proof
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eCFR. 26 CFR 1.274-5A – Substantiation Requirements
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Internal Revenue Service. Publication 463 – Travel, Gift, and Car Expenses
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Internal Revenue Service. Publication 551 – Basis of Assets
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Internal Revenue Service. Business Use of Home
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Internal Revenue Service. Publication 587 – Business Use of Your Home
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eCFR. 26 CFR 1.170A-15 – Substantiation Requirements for Charitable Contributions
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Office of the Law Revision Counsel. 26 USC 170 – Charitable, Etc., Contributions and Gifts
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Internal Revenue Service. Instructions for Form 8283
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Internal Revenue Service. Topic No. 305, Recordkeeping
15
Internal Revenue Service. Independent Contractor (Self-Employed) or Employee?
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Internal Revenue Service. Revenue Procedure 97-22
17
Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection
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Internal Revenue Service. How Long Should I Keep Records
19
Justia Law. Cohan v. Commissioner of Internal Revenue, 39 F.2d 540
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Office of the Law Revision Counsel. 26 U.S. Code 6662 – Imposition of Accuracy-Related Penalty on Underpayments
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Internal Revenue Service. Accuracy-Related Penalty
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Office of the Law Revision Counsel. 26 U.S. Code 6663 – Imposition of Fraud Penalty