Depreciation is one of the most powerful tax benefits of owning rental property — it reduces your taxable income without requiring any cash outlay. Understanding how to calculate it correctly ensures you're claiming every dollar you're entitled to and not leaving money on the table at tax time.
The IRS allows you to deduct the cost of rental property over its useful life. For residential rental property, that's 27.5 years. For commercial property, it's 39 years. You spread the building value (not land) across those years in equal annual deductions. This is called straight-line depreciation.
Your depreciable basis is the building value only — land is not depreciable. Start with your purchase price, then subtract land value. County tax records typically show the split between land and improvement value. For example: $300,000 purchase price, $40,000 land value = $260,000 depreciable basis.
Add to your basis: closing costs attributable to the property, any capital improvements made before placing the property in service. Subtract: any seller-paid points or credits that reduce your basis.
Divide your depreciable basis by 27.5 years. Example: $260,000 ÷ 27.5 = $9,454.55 per year in depreciation deductions. This reduces your taxable rental income by $9,454 annually — at a 32% tax bracket, that's a $3,025 annual tax saving from depreciation alone.
In the year you place property in service, you only get a partial year of depreciation based on the month you started renting. The IRS uses the mid-month convention — property placed in service in March earns depreciation for 9.5 months of the first year.
Keep a depreciation schedule that tracks the original basis, annual deductions taken, and accumulated depreciation. This is critical for calculating depreciation recapture when you eventually sell. Your tax software or CPA should maintain this schedule for you.
Dan White is a licensed Virginia real estate agent at Pearson Smith Realty and founder of FreeDealCalc.com. He has been investing in Northern Virginia real estate for 20+ years.