Tax Audit for Proprietors: When It Applies, Turnover Limits and Books of Account

A proprietorship has light compliance, but it isn't compliance-free. Once the business grows past certain limits, the proprietor has to keep proper books of account, and above higher limits, get those accounts audited by a chartered accountant before filing the income tax return. Missing a tax audit is expensive. This guide explains when the rules apply.

The limits below are those for FY 2025-26. From April 2026, the Income-tax Act, 2025 replaces the 1961 Act, carrying over these rules under new section numbers, so check the current limits for later years.

Books of Account

A proprietor running a business generally has to keep books of account if, in any of the three previous years, business income was more than ₹2.5 lakh or turnover was more than ₹25 lakh. Professionals, such as doctors, lawyers, architects, engineers and accountants, have to keep books once their gross receipts cross ₹1.5 lakh in each of the three previous years.

Proprietors using presumptive taxation generally don't need to keep detailed books for that business, as long as they stay within the scheme.

When a Tax Audit Applies

For businesses

• A tax audit is required if turnover is more than ₹1 crore.
• That limit rises to ₹10 crore if cash receipts are no more than 5% of total receipts, and cash payments are no more than 5% of total payments. Most digital-first businesses qualify for the higher limit.

For professionals

• A tax audit is required if gross receipts are more than ₹50 lakh.
• For professionals using presumptive taxation, the limit is ₹75 lakh, as long as cash receipts are no more than 5% of the total.

When you opt out of presumptive taxation

A proprietor who has used presumptive taxation and then declares profits lower than the presumptive rate, with total income above the basic exemption limit, may need a tax audit even below the usual turnover limits. The rules here are detailed, so check before switching between schemes.

What the Audit Involves

A chartered accountant examines the books and records and reports on them in the prescribed tax audit report, covering items such as:

• The method of accounting and stock valuation.
• Payments to related persons, and expenses that aren't deductible.
• TDS compliance on payments made.
• GST and other indirect tax details.
• Loans taken and repaid, and cash transactions above set limits.

Good bookkeeping through the year makes the audit much quicker.

Due Dates

• The tax audit report is generally due by 30 September after the end of the financial year.
• The income tax return for audited proprietors is generally due by 31 October.

These dates are sometimes extended, but don't plan around an extension.

Penalty for Missing It

Failing to get the accounts audited, or to file the audit report, can attract a penalty of up to 0.5% of turnover or gross receipts, capped at ₹1.5 lakh, unless there was a reasonable cause.

Practical Tips

• Track turnover and cash receipts through the year, so you know early if an audit will apply.
• Move payments and receipts to banking channels to stay within the higher limit.
• Keep the business bank account separate from personal accounts.
• Engage your CA well before 30 September.

Getting Help

Think Filing keeps books for proprietors, tracks the audit limits through the year, and handles tax audits and returns on time.

Sources

• Income-tax Act, 1961, sections 44AA, 44AB, 44AD and 44ADA, for FY 2025-26.
• Income-tax Act, 2025, from 1 April 2026.