Koste Chartered Quantity Surveyors 1300 669 400  |  info@koste.ai

Owning Property · Koste Knowledge Base

What is a CGT Cost Base Evidence Report?

Published 26 June 2026 · Last updated 26 June 2026

Quick Answer

A CGT Cost Base Evidence Report is a detailed document that outlines the original purchase price, improvements, and associated costs of a property. It's crucial for calculating capital gains tax (CGT) when selling an investment property. This report helps ensure all eligible costs are included, potentially reducing CGT liability.

When selling an investment property in Australia, understanding the capital gains tax (CGT) implications is crucial. A CGT Cost Base Evidence Report is a vital tool for investors, accountants, and property professionals, providing a comprehensive breakdown of the property's cost base. This report includes the original purchase price, costs of improvements, and other associated expenses, ensuring all eligible costs are considered for CGT calculations.

How a CGT Cost Base Evidence Report Works

The CGT Cost Base Evidence Report itemizes all the costs associated with acquiring and improving a property. According to the Income Tax Assessment Act 1997, the cost base includes five elements: the property's acquisition cost, incidental costs of acquisition and disposal, non-capital costs of ownership, capital expenditure to increase or preserve the property's value, and capital expenditure to establish, preserve, or defend title or rights. A common misconception is that only the purchase price affects CGT calculations, but other costs can significantly impact the final tax liability.

How This Works in Practice

Consider a 3-bedroom house in Melbourne purchased for $800,000 in 2015. Over the years, the owner invested $50,000 in renovations and incurred $20,000 in legal and stamp duty costs. Upon selling the property for $1.2 million in 2023, the CGT Cost Base Evidence Report helps calculate the total cost base as $870,000. With a selling price of $1.2 million, the capital gain is $330,000. At a 37% marginal tax rate, and holding the property for more than 12 months, the CGT liability would be approximately $61,050 after applying the 50% CGT discount for individuals.

Professional Insight

In our experience, many investors overlook incidental expenses like legal fees and stamp duty when calculating their property's cost base, which can unnecessarily increase CGT liability. One thing we frequently see is investors failing to keep detailed records of renovation costs, which can prevent them from claiming eligible deductions. What most investors don't realise is that a well-prepared CGT Cost Base Evidence Report can significantly reduce the taxable capital gain by ensuring all possible costs are included. Additionally, properties held in joint names can complicate cost base calculations, as each party's share must be accurately reflected.

When Does the Answer Change?

The general principles of a CGT Cost Base Evidence Report can change in specific situations:

  • Properties Acquired Before 20 September 1985: These are generally exempt from CGT, making the report unnecessary.
  • Properties Held in a Self-Managed Super Fund (SMSF): Different rules apply regarding CGT calculations and discounts.
  • Partial Year Ownership: If you owned the property for less than 12 months, the 50% CGT discount does not apply.
  • Inherited Properties: Different rules apply to determine the cost base, often involving a market valuation at the date of death.

When Should You Seek Professional Advice?

Determining the correct cost base can be complex, depending on individual circumstances such as joint ownership, renovations, or holding periods. Engaging both your accountant and a Chartered Quantity Surveyor is advisable to ensure all eligible costs are included and correctly documented. This collaboration is crucial for accurate CGT calculations and can prevent costly errors.

What to Do Next

  • Gather All Documentation: Compile purchase records, renovation receipts, and legal documents.
  • Consult a Chartered Quantity Surveyor: Obtain a CGT Cost Base Evidence Report tailored to your property.
  • Discuss with Your Accountant: Ensure the report aligns with your overall tax strategy.
  • Review Ownership Structure: Check how joint ownership or SMSF rules affect your situation.
  • Plan for Future Sales: Use the report to strategise future investment decisions.
  • Stay Informed: Keep updated on any legislative changes impacting CGT calculations.
  • Frequently Asked Questions

    What costs are included in a CGT Cost Base Evidence Report?

    The report includes acquisition costs, incidental costs, non-capital ownership costs, capital improvements, and any related legal expenses.

    How does a CGT Cost Base Evidence Report affect my tax return?

    It ensures all eligible costs are included in the CGT calculation, potentially reducing your taxable gain and overall tax liability.

    Is a CGT Cost Base Evidence Report necessary for properties in Victoria?

    Yes, the report is applicable across all Australian states, including Victoria, to accurately calculate CGT.

    Can I use a CGT Cost Base Evidence Report for an inherited property?

    Yes, but different rules may apply, such as using market value at the time of inheritance to establish the cost base.

    What happens if I don't have a CGT Cost Base Evidence Report?

    Without the report, you risk missing eligible deductions, which could increase your CGT liability.

    Related Articles

    Read Full Article Free Calculator
    CGTcapital gains taxcost baseinvestment propertytax deductionsproperty taxreal estateaccounting

    Written by Koste Team · Koste Chartered Quantity Surveyors · AIQS Member · RICS Member · TPB Registered · 1300 669 400 · info@koste.ai