As a sole trader in New Zealand, what are the rules for claiming home office expenses, and can I use the actual costs method?

Sole traders operating a business from home in New Zealand can claim deductions for the business use of their home, provided the expenses are directly related to earning business income. There are two primary methods for calculating these deductions: the Actual Costs Method and the Prescribed Rate Method (though the latter is often less common for detailed expense tracking).

### Actual Costs Method

The Actual Costs Method requires you to calculate the portion of your household running costs that are attributable to your business use. This is generally based on the proportion of the home used for business and the time spent using it for business purposes.

Steps for Calculation:

• Determine the Business Area: Calculate the floor area of the dedicated space used exclusively for business (e.g., an office room). If the space is used for both business and private purposes (e.g., a kitchen table), you must apportion the use based on time and space.
• Identify Total Household Costs: This includes costs like mortgage interest (if applicable), rent, rates, insurance, electricity, gas, repairs, and maintenance.
• Apportion Costs: The portion of these costs attributable to business use is calculated using the formula:

$$\text{Deductible Amount} = (\text{Total Household Costs}) \times (\frac{\text{Business Floor Area}}{\text{Total Floor Area}}) \times (\text{Business Use Percentage})$$

For example, if 15% of your home's floor area is a dedicated office, and you use it 100% of the time for business, you can deduct 15% of your total household running costs.

### Specific Expense Considerations

• Mortgage Interest vs. Rent: If you own your home, you can deduct the interest portion of your mortgage payments, but not the principal repayments. If you rent, you can deduct the rent portion.
• Capital Gains Tax (Bright-Line Test): Be aware that if you claim deductions for the use of your home for business, the IRD may argue that the portion of the home used for business is not your main private residence when calculating any potential Bright-Line Test liability upon sale, although specific guidance exists to mitigate this if records are sound.
• Utilities: Electricity and phone bills need careful apportionment. If you have a dedicated business phone line, the full cost is deductible. For general power, the area/time method applies.

Accurate record-keeping, including floor plans and detailed records of household expenses, is essential to support claims under the Actual Costs Method.