Inherited Property Cost Basis Calculation: Step-Up Rules and Tax Savings

The tax basis of inherited real estate generally isn't what your parent paid for the house. Under IRC Section 1014, the cost basis of inherited property resets to its fair market value on the date of death — a rule called the "stepped-up basis" that can save heirs tens of thousands of dollars in capital gains tax. But only if you document it correctly.

How the Stepped-Up Basis Works

For inherited real estate, the new tax basis is generally the property's fair market value on the date of death. This means decades of appreciation are effectively erased for tax purposes.

The calculation is straightforward:

Taxable Capital Gain = Sale Price - Stepped-Up Basis - Post-Death Improvements

If a parent bought a home in 1988 for $120,000 and it's worth $550,000 when they die in 2026, the heir's basis is $550,000. Sell the home for $560,000 a few months later, and the taxable gain is only $10,000 — not the $440,000 it would be under the original purchase price.

Without the step-up, that $440,000 gain at a 15% federal long-term capital gains rate would cost $66,000 in taxes. The step-up reduces the bill to $1,500.

Get the Date-of-Death Appraisal Immediately

The stepped-up basis is only as defensible as the documentation behind it. The IRS can challenge your claimed basis years later, and without a professional appraisal, you're guessing — and guesses don't hold up in an audit.

Hire a licensed residential appraiser to prepare a formal retrospective valuation as of the exact date of death. This costs $500 to $800 for a standard single-family home. The appraiser uses comparable sales from around the date of death, not current market values.

Timing matters. Schedule the appraisal as soon as possible after death, while the property's condition matches what it looked like on the date of death. If you renovate, repair, or clean out the property before the appraisal, the appraiser may be working with a different property than what existed at the date of death.

Keep the appraisal permanently. There is no statute of limitations on the IRS challenging a cost basis claim if the original return was never filed or was fraudulent. Even for standard audits, the IRS has three years from filing (six years if income is understated by more than 25%).

The Alternate Valuation Date

The executor can elect to use a value six months after the date of death instead of the date-of-death value — but only if doing so reduces both the value of the gross estate and the estate tax liability. This election (made on the federal estate tax return, Form 706) is typically relevant only for very large estates subject to the federal estate tax. For most inherited properties, the date-of-death value is the correct basis.

Capital Gains When You Sell

If you sell the inherited property, you owe federal capital gains tax only on appreciation that occurred after the date of death. The rate depends on your income and how long you held the property after inheriting it:

• Held more than one year after the date of death: long-term capital gains rates (0%, 15%, or 20% depending on income)
• Held one year or less: short-term capital gains rates (ordinary income tax rates, up to 37%)

For inherited property, the holding period is automatically treated as long-term regardless of how long you actually owned it — as long as the property was a capital asset in the deceased's hands. This means even a sale one week after inheriting qualifies for the lower long-term rate.

Additionally, the 3.8% Net Investment Income Tax (NIIT) applies if your modified adjusted gross income exceeds $200,000 (single) or $250,000 (married filing jointly).

State Inheritance and Estate Taxes

The federal stepped-up basis rule applies everywhere, but some states layer additional taxes on inherited real estate:

State inheritance taxes (charged to the heir) exist in five states: Kentucky, Maryland, Nebraska, New Jersey, and Pennsylvania. Rates and exemptions vary by the heir's relationship to the deceased — spouses are typically exempt, children often face lower rates, and unrelated heirs face the highest rates. Maryland is unique in imposing both an inheritance tax (10%) and an estate tax.

State estate taxes (charged to the estate before distribution) apply in twelve states plus the District of Columbia, with exemption thresholds much lower than the federal level. For example, Oregon's estate tax kicks in at $1 million, and Massachusetts at the same threshold — both well below the federal threshold, which applies to very large estates.

State capital gains taxes apply when you sell. California, Hawaii, and New Jersey have among the highest state capital gains rates. Some states (like Florida, Texas, and Washington) have no state income tax at all, meaning no state capital gains tax on the sale.

Common Mistakes That Cost Heirs Money

Using the original purchase price as basis. Heirs who don't know about the stepped-up basis rule — or who can't prove the date-of-death value — sometimes report the parent's original purchase price. This inflates the gain and costs thousands in unnecessary taxes.

Failing to track post-death improvements. Capital improvements you make after inheriting (a new roof, HVAC replacement, major renovation) add to your basis and reduce your taxable gain. Keep receipts for everything. Routine maintenance doesn't count — only improvements that add value or extend the home's useful life.

Ignoring the Section 121 exclusion. If you move into the inherited home and use it as your primary residence for at least two of the five years before selling, you can exclude up to $250,000 ($500,000 for married couples) of capital gains under the primary residence exclusion. This stacks on top of the stepped-up basis.

The Property & Real Estate Transfer After Death toolkit includes a stepped-up basis worksheet and a property expense ledger to help you track everything you need for a clean tax calculation — from the date-of-death appraisal to post-inheritance improvements.