Audit

Published Monday 17 August 2026

Table of contents

• What is an audit?
• Types of audits
• What triggers an audit?
• The audit process
• Audit standards and who sets them
• What the audit outcome means
• What auditors can and can't do
• Why audits matter
• Your rights and responsibilities in an audit
• What happens after an audit?
• How long to keep records for an audit
• How to prepare for an audit
• Keep your financial records organised with Xero
• FAQs on audits
• Related terms
• Learn more about audits

Key takeaways

• An audit is an independent examination of financial records, statements, or tax returns to verify accuracy and compliance with applicable laws or accounting standards.
• Audits can be conducted by tax authorities, external accountants, or internal teams, and they range from tax audits to compliance, operational, and IT audits.
• Keeping organised, up-to-date financial records year-round is one of the most effective ways to prepare for an audit and reduce stress if one occurs.
• You generally have the right to professional representation, fair treatment, and the ability to appeal or dispute audit findings.

What is an audit?

An audit is an independent examination of your financial records, statements, or tax returns to confirm they are accurate and complete. For small business owners, audits most commonly involve a tax authority reviewing a tax return, but they can also include internal reviews or third-party evaluations of your financial statements.

The word "audit" comes from the Latin "audire", meaning "to hear". Historically, auditors would listen to verbal accounts of financial transactions to verify their accuracy. Today, the goal of any audit is to verify that the figures you have reported match your actual financial activity. Audits can be routine, random, or triggered by specific concerns in your records.

Types of audits

Not all audits work the same way. The type of audit you encounter depends on who is conducting it and why.

• Tax audit: Conducted by a tax authority to verify the accuracy of your tax return. Tax audits can be handled by mail or in person at a tax office or your place of business.
• External (financial statement) audit: Performed by an independent certified public accountant or accounting firm. External audits provide an objective opinion on whether your financial statements are fairly presented. Lenders, investors, and regulatory bodies often require them.
• Internal audit: Carried out by someone within your organisation, or a hired consultant, to evaluate your internal controls, processes, and risk management. Internal audits help you catch errors and inefficiencies before they become bigger problems.
• Compliance audit: Focuses on whether your business is following specific laws, regulations, or industry standards. For example, a compliance audit might check that you are meeting payroll tax requirements or adhering to data protection rules.
• Operational audit: Examines the efficiency and effectiveness of your business operations, looking for ways to improve processes and reduce waste.
• IT audit: Reviews your information technology systems, controls, and data security practices to identify vulnerabilities and confirm compliance with relevant standards.
• Forensic audit: Investigates suspected fraud, embezzlement, or financial misconduct by examining records in detail to uncover irregularities.
• Quality and ISO audits: Assess whether your business meets specific quality management standards, such as ISO 9001 or ISO 14001, often required for industry certifications.

What triggers an audit?

Understanding what prompts tax authorities or auditors to look more closely at your records can help you avoid common mistakes. While triggers vary by country and audit type, some general factors increase your chances of being selected.

• Document mismatches: If the income reported on your return does not match information that your tax authority receives from employers, banks, or other third parties, your return may be flagged.
• Unreported income: Failing to report all sources of income is one of the most common audit triggers.
• Unusually large deductions: Claiming deductions that are disproportionately large compared to your reported income, such as excessive home office or vehicle expenses, can draw attention.
• Random selection: Some returns are chosen purely at random as part of government research or compliance programmes.
• Related-party reviews: If a business partner, investor, or related party is being audited, your records may also be reviewed.

The audit process

Whether you are facing a tax audit or a financial statement audit, the process typically follows a structured series of stages. Knowing what to expect makes it easier to respond.

1. Notification or engagement

For a tax audit, you receive a letter from the tax authority explaining which return is being reviewed and what information you need to provide. For a financial statement audit, you engage an external auditor and agree on the scope and timeline.

2. Gathering records

You collect the records specified in the notification or agreed with the auditor. This usually includes receipts, bank statements, invoices, and any documentation that supports the items being reviewed.

3. Fieldwork and review

The auditor examines your records, tests transactions, and reviews your internal controls. This may involve on-site visits, interviews, or correspondence depending on the audit type.

4. Findings and reporting

Once the review is complete, you receive a letter or report with the auditor's findings. For tax audits, you typically have the option to agree, partially agree, or disagree with the results. For financial audits, the auditor issues a formal opinion.

Audit standards and who sets them

Professional audits follow established standards to ensure consistency and reliability. The main bodies that set these standards include the following.

• GAAS (Generally Accepted Auditing Standards): The framework used primarily in the United States for audits of private companies, set by the American Institute of Certified Public Accountants (AICPA).
• International Standards on Auditing (ISA): Developed by the International Auditing and Assurance Standards Board (IAASB), these standards are used in many countries around the world and provide a global benchmark for audit quality.
• ISO 19011: Provides guidelines for auditing management systems, such as quality (ISO 9001) or environmental (ISO 14001) management systems, and is published by the International Organisation for Standardisation.

What the audit outcome means

For financial statement audits, the auditor issues an opinion that indicates how much confidence readers can place in the statements. The four main types of audit opinions are listed below.

• Unqualified (clean) opinion: The financial statements present a true and fair view with no material misstatements. This is the best outcome.
• Qualified opinion: The financial statements are mostly accurate, but there are specific areas where the auditor found issues or could not obtain sufficient evidence.
• Adverse opinion: The financial statements contain material misstatements and do not present a true and fair view. This is a serious concern.
• Disclaimer of opinion: The auditor was unable to obtain enough evidence to form an opinion on the financial statements, often due to significant limitations on the audit scope.

What auditors can and can't do

Understanding the scope of an audit helps set realistic expectations. Audits provide reasonable assurance, not absolute certainty, that financial statements are free from material misstatement.

• Auditors test transactions on a sample basis rather than examining every single record, so some errors may go undetected.
• An audit is not a fraud investigation. While auditors consider the risk of fraud, a standard audit is not designed to detect all fraudulent activity.
• Auditors assess whether controls are adequate but cannot guarantee that your business will never experience errors or misconduct.

Why audits matter

Audits serve a purpose beyond checking boxes for compliance. They can be genuinely useful for your business.

• Compliance: Audits confirm that your business is meeting its tax obligations and following applicable regulations. Staying compliant helps you avoid penalties, interest charges, and legal issues.
• Credibility: A clean audit history builds trust with lenders, investors, and potential partners. If you are applying for a business loan or seeking outside funding, audited financial statements carry more weight.
• Better decision-making: Preparing for an audit often reveals gaps in your record keeping or small business accounting processes. Addressing these gaps gives you clearer, more reliable data to base decisions on.
• Error detection: Audits can uncover bookkeeping mistakes, duplicate entries, or missed deductions that you might not have caught on your own.

Your rights and responsibilities in an audit

If you are audited, you have rights that protect you throughout the process. While specific rights vary by country, the following principles generally apply.

• Right to professional representation: You can have a tax professional, such as an accountant, tax agent, or attorney, represent you during an audit. You do not have to face auditors alone.
• Right to fair and courteous treatment: Auditors are expected to treat you with respect. If you feel you have been treated unfairly, you can typically report it to the relevant authority.
• Right to appeal or dispute findings: If you disagree with the audit findings, you generally have the right to challenge them through an internal review or formal appeals process.
• Right to confidentiality: Your financial information should be kept confidential and not shared with outside parties without your authorisation, except as required by law.

Your responsibilities include responding to audit requests within the required timeframes, providing accurate and complete information, and maintaining organised records that support the figures on your returns or statements.

What happens after an audit?

Once the auditor finishes reviewing your records, there are several possible outcomes.

• No change: The auditor finds that everything on your return or in your financial statements is accurate. No additional taxes, penalties, or adjustments are needed.
• Agreed adjustments: The auditor proposes changes, and you agree with them. You sign off on the findings and, for tax audits, pay any additional tax owed plus interest.
• Disagreement: You do not agree with the auditor's findings. In this case, you can request a meeting with a supervisor, file a formal appeal, or, in some jurisdictions, take the matter to a tax tribunal or court.

How long to keep records for an audit

Record retention requirements vary by country and the type of records involved. Keeping your documents organised and accessible is essential if an audit occurs years after the original filing.

In the US, for example, the standard statute of limitations for tax audits is three years from the filing date. This extends to six years if income is understated by more than 25%, and there is no time limit for fraudulent or unfiled returns. Because of these rules, tax professionals commonly recommend keeping tax records for at least seven years.

Regardless of where your business operates, maintaining good records makes audits less stressful and helps with regular tasks like bank reconciliation and financial reporting. Check with a local accountant or tax professional to understand the specific requirements in your jurisdiction.

How to prepare for an audit

The best time to prepare for an audit is before you are ever notified of one. Good financial habits year-round make the process far less stressful. Follow these steps to stay audit-ready.

1. Keep thorough records

Save receipts, invoices, bank statements, and any documents that support items on your tax return or financial statements. Digital copies are acceptable and easier to organise.

2. Reconcile accounts regularly

Match your bank and credit card transactions to your books at least monthly. Regular reconciliation catches errors early and keeps your records accurate.

3. Separate business and personal finances

Use a dedicated business bank account and credit card. Mixing personal and business expenses creates confusion and makes it harder to substantiate deductions.

4. Document deductions carefully

For each deduction you claim, keep proof of the amount, the business purpose, and the date. This is especially important for travel, meals, and vehicle expenses.

5. Review your return before filing

Double-check that all income sources are reported and that the figures on your return match your supporting documents.

6. Get professional help

An accountant or tax professional can help you file accurately and represent you if an audit occurs. Their expertise is especially valuable for complex returns.

7. Store records securely

Keep your tax records and supporting documents for the period required in your jurisdiction. Storing records digitally in cloud accounting software makes it simpler to access past documents quickly if needed.

Keep your financial records organised with Xero

Staying audit-ready starts with keeping your financial records accurate and easy to access. Xero connects to your bank to pull in transactions automatically, helping keep your books up to date. With features like automated bank reconciliation, digital receipt capture, and customisable financial reports, Xero gives you the tools to stay on top of your finances and reduce manual effort. If an audit ever comes your way, you will have the records you need in one place. Get one month free.

FAQs on audits

Here are answers to some frequently asked questions about audits.

How long does an audit take?

A simple correspondence audit can wrap up in a few months, while more complex field audits may take over a year. The timeline depends on the issues being reviewed, how quickly you provide documentation, and the auditor's workload.

Can you be audited if you don't file taxes?

Yes. If you do not file a return, the tax authority can file a substitute return on your behalf and assess taxes owed. In many jurisdictions, there is no time limit for auditing unfiled returns.

How much does a small business audit cost?

The cost depends on the type of audit. A tax audit by a government authority has no direct fee, but you may incur costs for professional representation, ranging from a few hundred to several thousand dollars. A voluntary external financial audit by an accounting firm varies widely based on business size and complexity.

Do small businesses get audited more than individuals?

Not necessarily. Tax authorities audit a relatively small percentage of all returns each year. However, sole proprietors and businesses with significant cash transactions or large deductions relative to income may face higher scrutiny.

What documents do you need for an audit?

You will typically need bank statements, receipts, invoices, payroll records, prior tax returns, and any documents that support the income and deductions on the return or statements being audited. The notification letter or engagement agreement specifies exactly which records to provide.

Related terms

• Balance sheet
• Cash flow
• General ledger

Learn more about audits

• How to do bookkeeping
• What does an accountant do
• General ledger and recording transactions