CRA personal audit: what triggers one and how to prepare

What triggers a CRA personal audit

CRA uses automated risk-scoring software to compare your return against statistical norms for your income level, occupation, and province. Returns that deviate significantly from expected patterns, or that contain items CRA is focusing on in a given year, get flagged for review. Common personal audit triggers include:

Unreported income

CRA receives copies of every T-slip issued to you: T4 (employment), T4A (pensions, self-employment), T5 (investment income), and many others. Their matching system compares the slips on file against what you reported. If a T4 shows $80,000 in employment income and you only reported $60,000, the discrepancy triggers an immediate query. Always include all T-slips, even for small amounts — even a forgotten T5 for $12 of bank interest can result in a review request.

Large or unusual deductions

Deductions that are large relative to your income or that are consistently claimed year after year attract scrutiny. Home office expenses, particularly those claimed by employees using Form T777, are a perennial focus area. CRA also looks closely at vehicle expenses where the business-use percentage claimed seems high, and at employment expense claims in general.

Rental property losses

Rental income and expenses are a common area of audit focus. CRA expects rental properties to generate income in the long run — a rental that consistently produces losses (especially a property you also personally use) may be challenged as a personal endeavour rather than a business. Ensure all rental income is reported and that expenses like maintenance, mortgage interest, and property taxes are supported by receipts and actual payment records.

Home office claims

Both employees and self-employed individuals can claim home office expenses, but the rules differ. Employees must have Form T2200 signed by their employer confirming the requirement to maintain a home office. Self-employed individuals can claim the business-use portion of their home expenses, but "business-use" must be supported by a clear calculation. CRA auditors look at whether the claimed workspace is used exclusively for business and regularly enough to justify the deduction.

Large charitable donations

CRA screens for charitable donation claims that seem disproportionate to income. Donation tax shelter schemes — arrangements that promised tax receipts greater than the actual cash donation — have been heavily targeted by CRA. Legitimate charitable donations are absolutely deductible, but keep the official receipts, and be very cautious of any arrangement that claims to generate a tax benefit greater than the actual cash you donated.

Foreign income and assets

Canadians with foreign income, foreign bank accounts, or foreign property worth more than $100,000 must file Form T1135 (Foreign Income Verification Statement). Failure to file this form — or underreporting foreign income — is a common audit trigger. CRA receives information from foreign tax authorities through tax information exchange agreements, so offshore income is less hidden than many taxpayers assume.

Self-employment income

Self-employed individuals file a T2125 (Statement of Business or Professional Activities). CRA pays close attention to the ratio of expenses to gross income in various professions. Unusually high expense claims — meals and entertainment over 50%, vehicle expenses claiming 100% business use, or large equipment purchases in a service business — can all flag a return for review.

Audit timeline: notification to reassessment

A typical CRA personal audit follows this sequence. The total time from notification to final outcome is usually three to six months for a simple audit, but can stretch to a year or more for complex situations or if there are delays in providing documents.

If the audit results in no changes to your return, CRA will notify you that the review is complete and your return is accepted as filed. This is actually a common outcome — CRA audits often close without any changes when taxpayers have complete documentation.

Documents to gather

The moment you receive an audit notification, start assembling documentation. Even if CRA hasn't specified exactly what they want yet, having organized records significantly speeds up the process. Core documents include:

Employment and income records

• All T4, T4A, T5, T3, T4RSP, and other income slips for the year under review
• Final pay stubs for the year
• Employment contracts if you claim unusual deductions
• Records of any cash income, tips, or side payments

Bank and investment statements

• Full year bank statements for all personal and business accounts
• Investment account statements showing purchases, dispositions, and income
• Foreign account statements and records of any foreign income
• RRSP contribution receipts and statements

Expense receipts

• Original receipts for all claimed deductions — not just credit card statements
• Home office records: mortgage statement or lease, utility bills, internet bills, and a floor plan showing the office proportion
• Vehicle logbook showing business vs. personal kilometres
• Medical expense receipts for anything claimed on the Medical Expense Tax Credit
• Charitable donation receipts from registered Canadian charities

Property records

• Purchase and sale documents for any real estate sold during the year
• Rental income records: leases, rent receipts, deposit records
• Renovation and maintenance receipts if you deducted them as rental expenses

Organize everything chronologically and create an index. If you are working with a CPA, they will advise you on how to present documents to CRA most effectively.

Your rights as a taxpayer

CRA's Taxpayer Bill of Rights outlines 16 rights. The most important ones during an audit:

Right to be informed

You have the right to receive clear, accurate information about the audit and what CRA is examining. If an auditor's request is unclear, ask for clarification in writing.

Right to professional representation

You have the right to have a CPA, tax lawyer, or authorized representative communicate with CRA on your behalf at any time. You do not have to speak directly with an auditor if you prefer your representative to handle all communication. File Form T1013 to authorize your representative.

Right to a 30-day response window

CRA's proposal letters typically give you 30 days to respond. If you need more time — because you are gathering documents, consulting a professional, or waiting for information — you can generally request an extension. Get the extension confirmation in writing or by asking for it in your response to their letter.

Right to object

If you disagree with a Notice of Assessment or Reassessment, you have 90 days from the date on the notice to file a Notice of Objection. This deadline is strict — missing it means you lose the right to object at the CRA level (though you may still be able to apply for an extension or go to Tax Court).

Right to complain

If you believe a CRA auditor has treated you unfairly, you can complain to the CRA's Taxpayers' Ombudsperson, an independent officer who investigates service complaints about CRA.

What CRA cannot do

CRA auditors cannot enter your home without your permission (unless they have a court-issued warrant). They cannot demand documents outside the normal scope of the audit without proper authority. They cannot seize your property without following the legal process for collection actions. They must treat you with courtesy and professionalism.

What to do if you disagree with the outcome

If CRA reassesses your return and you believe they are wrong, you have a structured process for challenging the assessment:

Step 1: Notice of Objection (90-day deadline)

File Form T400A (Notice of Objection) within 90 days of the date on your Notice of Assessment or Reassessment. You can file online through My Account, by mail to your tax services office, or through a representative. In the objection, explain clearly why you disagree with each proposed change and attach supporting documentation you may not have provided during the audit.

Important: Even if you cannot pay the reassessed amount immediately, file the objection on time. An objection generally suspends the collection of the disputed amount while CRA reviews it (with some exceptions for source deductions and GST/HST).

Step 2: CRA Appeals Division review

Your objection goes to CRA's Appeals Division, which is separate from the audit function. An appeals officer reviews the file independently and may contact you for additional information. This process typically takes one to three years due to CRA's backlog. If the appeals officer agrees with you, they will vary or vacate the assessment. If they agree with CRA's original position, they will confirm the assessment.

Step 3: Tax Court of Canada

If the Appeals Division confirms the assessment and you still disagree, you can appeal to the Tax Court of Canada within 90 days of receiving the confirmation. Tax Court has two procedures: the Informal Procedure for disputes under $25,000 (fast, low-cost, you can represent yourself) and the General Procedure for larger amounts (more formal, typically requires a tax lawyer). See our Tax Objections & Appeals guide for full details.

Frequently asked questions