Quick Answer
Your home's cost basis starts with your purchase price plus eligible closing costs (typically $5,000-$15,000), then add capital improvements over time. For a $400,000 home with $10,000 closing costs and $50,000 in improvements, your basis would be $460,000 — reducing capital gains by $60,000 when you sell.
Best Answer
Robert Kim, CPA
Primary residence owners who plan to sell or use part of their home for business
What is cost basis and why it matters
Your home's cost basis is the total amount you've invested in the property for tax purposes. This number directly impacts your capital gains when you sell and determines depreciation if you use part of your home for business. According to IRS Publication 551, "Your basis is usually what you paid for the property plus certain costs and expenses."
Most homeowners leave thousands of dollars on the table by failing to track their full basis correctly.
Step 1: Start with your purchase price
Your basis begins with what you actually paid for the home, not the listed price. This includes:
Example: You bought a home listed at $425,000 but negotiated down to $400,000. Your starting basis is $400,000.
Step 2: Add eligible closing costs
Many closing costs increase your basis immediately. Per IRS Publication 523, these include:
Do NOT add: Loan origination fees, appraisal fees, credit report costs, or mortgage insurance (these are loan costs, not property costs).
Example calculation: Complete cost basis
Step 3: Track capital improvements
Capital improvements that add value, extend the home's life, or adapt it to new uses increase your basis. According to IRS Publication 523, this includes:
Do NOT add: Routine maintenance and repairs that don't add value or extend life.
Continuing the example: 10 years of improvements
Special situations that affect basis
What you should do
1. Gather your closing documents and identify basis-eligible costs
2. Create a home improvement file and save all receipts for capital improvements
3. Use the return-scanner tool to check if you've claimed all eligible deductions
4. Keep organized records — you may not sell for years, but you'll need this documentation
Key takeaway: A $400,000 home typically has a true cost basis of $450,000-$500,000 after closing costs and improvements. Tracking this correctly can save $10,000-$15,000 in capital gains taxes when you sell.
*Sources: [IRS Publication 551](https://www.irs.gov/pub/irs-pdf/p551.pdf), [IRS Publication 523](https://www.irs.gov/pub/irs-pdf/p523.pdf)*
Key Takeaway: Your home's cost basis includes purchase price, eligible closing costs, and all capital improvements — typically $50,000-$100,000 more than homeowners realize.
Common closing costs and their impact on cost basis
| Closing Cost Item | Typical Amount | Adds to Basis? | Tax Treatment |
|---|---|---|---|
| Title insurance | $800-$2,000 | Yes | Increases basis |
| Recording fees | $200-$500 | Yes | Increases basis |
| Survey costs | $300-$700 | Yes | Increases basis |
| Legal fees (purchase) | $500-$2,000 | Yes | Increases basis |
| Inspection fees | $300-$600 | Yes | Increases basis |
| Loan origination | $1,500-$3,000 | No | Mortgage interest deduction |
| Appraisal | $400-$800 | No | Not deductible |
| Credit report | $25-$50 | No | Not deductible |
More Perspectives
Michelle Woodard, JD
Investors who own rental properties and need to track depreciation basis
Investor-specific basis considerations
For rental properties, cost basis serves two critical purposes: calculating depreciation deductions and determining gain on sale. According to IRC Section 1012, your basis calculation follows the same rules as homeowners, but the tax implications are more complex.
Separating land from building value
Unlike personal residences, investors must allocate basis between land (non-depreciable) and building (depreciable). Use the property tax assessment ratio or get an appraisal.
Example: $500,000 purchase price
Depreciable basis vs. sale basis
Your depreciable basis (for annual depreciation) and sale basis (for capital gains) track differently:
After 5 years of depreciation:
Capital improvements for rental properties
Improvements to rental property increase basis differently:
What investors should track
1. Original purchase allocation between land and building
2. All capital improvements with dates and amounts
3. Annual depreciation taken (even if not claimed, it reduces basis)
4. Section 1031 exchanges that defer gain but carry forward basis
Key takeaway: Rental property basis tracking is more complex due to depreciation, but proper records can save thousands in taxes through maximized deductions and accurate gain calculations.
*Sources: [IRS Publication 527](https://www.irs.gov/pub/irs-pdf/p527.pdf), [IRC Section 1012]*
Key Takeaway: Rental property investors must separate land from building basis, track depreciation annually, and maintain detailed improvement records for complex gain calculations.
Robert Kim, CPA
Homeowners preparing to sell who need to minimize capital gains taxes
Pre-sale basis optimization strategy
If you're planning to sell within the next 1-2 years, now is the time to maximize your cost basis and minimize capital gains. According to IRS Publication 523, you have until the sale date to complete improvements that increase basis.
The $500,000 exclusion strategy
Married couples can exclude up to $500,000 of gain ($250,000 single) if they've owned and lived in the home 2 of the last 5 years. But if your gain exceeds this, every dollar of additional basis saves you 15-20% in capital gains tax.
Example scenario:
Quick wins to increase basis before sale
1. Review old receipts: Many homeowners forget improvements from years ago
2. Recent energy improvements: Solar, new HVAC, windows all count
3. Cosmetic improvements that add value: Quality flooring, kitchen updates
4. Complete projects in progress: Finish that bathroom remodel before listing
Documentation you need for closing
Your tax preparer will need:
Selling costs that reduce gain
While not technically part of basis, selling costs directly reduce your taxable gain:
On a $900,000 sale: 6% commission ($54,000) plus $3,000 other costs = $57,000 gain reduction
What to do now
1. Calculate your estimated gain using current market value
2. Gather all improvement documentation from your files
3. Consider strategic improvements if you're over the exclusion limit
4. Use the refund-estimator tool to see potential tax savings
Key takeaway: Every $1,000 of forgotten basis or strategic improvement saves $150-$200 in capital gains tax. The time to optimize is before you list, not at tax time.
*Sources: [IRS Publication 523](https://www.irs.gov/pub/irs-pdf/p523.pdf)*
Key Takeaway: Pre-sale basis optimization can save $7,500-$15,000 in capital gains taxes by documenting forgotten improvements and completing strategic projects before listing.
Sources
- IRS Publication 551 — Basis of Assets
- IRS Publication 523 — Selling Your Home
Related Questions
Reviewed by Robert Kim, CPA on February 28, 2026
This content is for educational purposes only and is not a substitute for professional tax advice. Consult a qualified tax professional for advice specific to your situation.