The home office deduction is available only when a space in a residence is used for business on a regular and exclusive basis or when it serves as the principal place of business. The authoritative guidance is in Publication 587 authored by the Internal Revenue Service, which outlines which expenses qualify and how to allocate them. Tax writer Stephen Fishman Nolo provides practical explanations consistent with that guidance.
Qualifying expense categories
Expenses fall into two main categories: direct expenses, which benefit only the business area, and indirect expenses, which benefit the whole home and must be prorated. Direct expenses such as painting or repairs that apply solely to the office are fully deductible. Indirect expenses include mortgage interest, property taxes, rent, utilities, homeowners insurance, general repairs, and depreciation; these are deductible only for the business portion, typically measured by the percentage of the home’s square footage devoted to the office or by a time-based allocation if the space is shared. The Internal Revenue Service describes an alternative simplified method that allows a flat deduction of five dollars per square foot up to three hundred square feet for taxpayers preferring not to calculate depreciation and prorated indirect costs; choosing the simplified method affects whether depreciation is claimed.
Allocation, consequences, and local nuance
In mixed-use residences where rooms serve both personal and business needs at different times, exclusive use is the key limitation: even frequent work in a kitchen or shared living area may disqualify the deduction if the space is not used solely for business. Improper allocations or claims can trigger audits, denial of the deduction, and potential recapture of depreciation when the property is sold, a treatment highlighted in Internal Revenue Service guidance and explained by Stephen Fishman Nolo. State and territorial tax rules may diverge from federal treatment, and cultural living arrangements—such as multigenerational households or small urban rentals—can complicate establishing exclusivity or measuring space. Because these factual and local variations affect both eligibility and tax outcomes, consulting a qualified tax professional is prudent to apply Publication 587 Internal Revenue Service guidance to specific circumstances.