Abstract:
The primary concern of this study is to examine the tax issues of the deductibility of mixed business and personal expenses. Under the income tax system, it would be necessary to allow taxpayers to deduct the costs associated with producing income. Thus, business expenses are generally deductible but personal expenses are not. Nevertheless, if the taxpayers are any person who engage in a trade or business there are many expenditures that difficult to make a distinction between business expenses and personal expenses such as the home office costs incurred in using part of taxpayers home for business and the rest for private activities so that special rules, for the purpose of classifying those expenses, may be required for determining the deductibility of mixed expenses. Under Thai laws, If taxpayers derived income from trade or business as stipulated in Section 40 (8) of the Revenue Code, their assessable incomes may be deducted under Section 46 of the Revenue Code and Section 8 of the Royal Decree Prescribing Expenses Deductible From Assessable Incomes under the Revenue Code, (No. 11) B.E.2502 (1959) which the taxpayers have two options for computing the deduction: the lump-sum deduction, and the actual deduction. If the taxpayers select the latter, the Section 65 bis of the Revenue Code and Section 65 ter of the Revenue Code, which are the provisions of calculation of net profit and net loss of companies, shall apply mutatis mutandis for the purpose of determine the net incomes of the taxpayers. However, the finding suggest that current Thai laws have no concept of mixed expenses as a result it have no any provision for tackling the deduction of those expenses Therefore, the study aim to analyze the problems arising from a lack of the concept of mixed expenses in Thai laws and to find the solutions by conducting based on the tax laws of the United States and Australia to provide guidelines for revising the Revenue Code of Thailand