How to Determine Cost Basis for Inherited Assets Before Selling

Think the price the person paid is your cost basis?
Think again.
For inherited assets, your basis usually becomes the fair market value on the decedent’s date of death, not the original purchase price.
That one number can change your tax bill by tens or hundreds of thousands of dollars.
This post gives clear steps to verify that value, use the six-month alternate if elected, and adjust for improvements or depreciation before you sell.
Pulling the right statements, appraisals, and Form 706 values now prevents costly surprises later.
If anything is unclear, we’ll show what to ask your tax pro.

How to Calculate Cost Basis for Inherited Assets Immediately

Your cost basis for inherited assets equals the fair market value on the decedent’s date of death. That FMV becomes your starting point for calculating capital gain or loss when you sell. If the estate elected to use the alternate valuation date on Form 706, your basis is the FMV six months after death (or the actual sale date if the asset was sold before the six month mark). This stepped up basis number flows directly onto Form 8949 when you report the sale, and from there to Schedule D on your federal return.

Verifying FMV before you sell prevents costly mistakes. The IRS expects contemporaneous evidence, not guesses made years later. Gather the strongest documentation you can find, ideally dated at or near the date of death.

Professional appraisal with an effective valuation date matching the date of death, signed by a qualified appraiser

Form 706 values if the estate filed a federal estate tax return, which are typically accepted as authoritative FMV evidence

Brokerage or custodial statements showing account balances and per share closing prices on the exact date of death

Real estate comparables from local multiple listing services or county assessor records for the specific month and year

Probate court valuations submitted by the executor or personal representative during estate administration

Alternate valuation date documentation if the estate elected the six month option on Form 706

Long term treatment applies automatically. You always enter the date acquired as the date of death and check the long term box on Form 8949, regardless of how long you held the asset.

Accurate basis determination can shift taxable gains by tens or even hundreds of thousands of dollars. Using the decedent’s original purchase price instead of the stepped up FMV typically inflates your capital gain, creating a much larger tax bill than you actually owe.

Key Rules Behind FMV and Stepped Up Basis for Inherited Assets

Stepped up basis and fair market value are two sides of the same coin. Under Internal Revenue Code Section 1014, most assets you inherit receive a cost basis equal to their FMV on the decedent’s date of death. This rule replaces the decedent’s original purchase price and resets your starting point for calculating gain or loss. The “step up” can also be a “step down” if FMV at death is lower than what the decedent originally paid.

Fair market value means the price a willing buyer would pay a willing seller, neither under pressure, both aware of relevant facts. For publicly traded stocks, FMV is the closing price on the date of death. For real estate and unique assets, you need a qualified appraisal that applies recognized valuation methods. Comparable sales, income capitalization, or replacement cost. All of these result in a defensible arm’s length estimate.

Estates may elect the alternate valuation date, which is six months after the date of death, on Form 706. This election applies to the entire estate, not asset by asset. If an asset is sold or distributed before the six month mark, its FMV on the actual transaction date becomes the basis. Form 706 must be filed within nine months of death (extensions available), and the alternate valuation date can only be elected if it reduces both the gross estate value and the estate tax liability.

What Are Adjusted Basis Factors for Inherited Property?

Your inherited basis isn’t always static. Capital improvements you make after the date of death increase your adjusted basis. Painting a room typically doesn’t count, but replacing a roof, adding a bathroom, or installing central air conditioning does. Keep invoices with dates and descriptions to document each improvement.

Depreciation works differently for inherited rental property. Your depreciation schedule starts fresh using the stepped up FMV as the depreciable basis, not the decedent’s remaining basis. Any depreciation you claim after inheriting the property reduces your adjusted basis dollar for dollar. When you sell, the IRS will recapture that depreciation and tax it at ordinary income rates (up to 25 percent), not capital gains rates. Selling costs like agent commissions, title fees, transfer taxes reduce your taxable gain at sale but don’t adjust basis. They’re subtracted from proceeds on Form 8949.

An example. You inherit a rental property with a stepped up basis of $300,000 and spend $20,000 on a new HVAC system two years later. Your adjusted basis climbs to $320,000. If you take $15,000 of depreciation during those two years, your adjusted basis drops to $305,000. When you sell for $350,000 and pay $10,000 in selling costs, your net proceeds are $340,000, and your capital gain is $340,000 minus $305,000, or $35,000. The $15,000 of depreciation will be recaptured and taxed as ordinary income.

Add documented capital improvements made after the date of death, supported by invoices showing date, scope, and amount paid.

Subtract allowable depreciation claimed on rental or business use property you held after inheriting.

Subtract selling costs from sale proceeds when calculating net gain or loss, not from basis directly.

Retain receipts and depreciation schedules to substantiate every adjustment if the IRS asks.

How to Determine Cost Basis for Inherited Assets Before Selling

How to Determine Basis Using the Date of Death

The date of death is your default valuation point. Pull FMV evidence as close to that exact date as possible. For stocks and mutual funds, use the closing price on the date of death. If markets were closed that day, use the average of the high and low on the nearest trading day. For real estate, order a retrospective appraisal that explicitly states the effective valuation date and provides a signed opinion of FMV as of that date.

Confirm the exact legal date of death from the death certificate.

Gather brokerage statements, custodial account summaries, or fund prospectuses showing values on that date.

For real estate, commission a qualified appraiser to produce a retrospective appraisal with an effective date matching the date of death.

For unique assets (collectibles, art, business interests), hire a specialist appraiser familiar with those asset classes.

Document FMV using at least two independent sources when possible. Broker statements and Form 706 values, or appraisal and county comparables.

How to Use the Alternate Valuation Date

If the estate elected the alternate valuation date on Form 706, your basis shifts to the FMV six months after death. This election is binding and applies to every asset in the estate. Check the filed Form 706 or ask the executor whether the election was made. The return must have been filed within nine months of death (or the extended deadline) to permit the election.

Review the filed Form 706 to confirm whether the alternate valuation date was elected and the exact six month anniversary date.

If the asset was sold or distributed before the six month date, use the FMV on the actual sale or distribution date instead.

Obtain appraisals or market quotes dated at the six month mark for assets still held by the estate at that time.

Use the alternate date values consistently across all reporting. Basis for all estate assets must reflect the same election.

How to Calculate Basis for Jointly Owned or Community Property

Ownership structure changes how much basis you receive. In joint tenancy with right of survivorship outside a community property state, only the decedent’s share (often 50 percent) gets stepped up to FMV. Your original share retains its historical basis. In community property states, both halves of community property typically receive a full step up to FMV upon the first spouse’s death.

Identify the form of ownership from the deed or account registration. Joint tenancy, tenants in common, or community property.

Determine each owner’s percentage interest. For joint tenancy, it’s usually equal shares.

In non community property states, calculate stepped up basis only for the decedent’s share: FMV at death × decedent’s percentage.

In community property states (Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, Wisconsin), apply a full step up to the entire FMV of community assets.

For tenants in common, step up only the portion owned by the decedent. Surviving co owners keep their original basis for their shares.

How to Adjust Basis for Improvements and Depreciation

Start with the stepped up FMV. Add the cost of any capital improvements you made after the date of death. Subtract allowable depreciation if the property generated rental or business income while you held it. Do not subtract the decedent’s prior depreciation. The step up at death erases that history.

List every capital improvement with invoice date, vendor, description, and amount paid.

Calculate total depreciation claimed on your tax returns since the date of death for rental or business use property.

Compute adjusted basis: FMV at death + improvements, minus depreciation taken by you.

Keep all supporting documents organized and readily available. Paid invoices, contractor agreements, depreciation schedules.

How to Prepare the Basis for Reporting on Form 8949

Form 8949 requires description, date acquired, date sold, sale proceeds, cost basis, and adjustments. For inherited assets, the date acquired is always the date of death (or alternate valuation date if elected), and sales are always treated as long term.

Enter the asset description exactly as it appears on the 1099-B or closing statement.

In the “Date Acquired” column, enter the decedent’s date of death, not the date you received title.

Check the long term box. Inherited assets are automatically long term regardless of holding period.

Report cost basis equal to the stepped up FMV at date of death, adjusted for any improvements or depreciation.

Attach a statement or note explaining the basis determination if the 1099-B shows a different (often zero or original purchase) basis.

Comparison of Different Inherited Asset Basis Scenarios

Different asset types follow the same stepped up basis rule, but documentation and practical steps vary. Real estate requires appraisals. Publicly traded stock needs only a broker quote. Gifts during the decedent’s lifetime carry over the donor’s basis and never receive a step up, creating a much larger taxable gain when sold.

The tax difference between inheriting property and receiving it as a lifetime gift can be enormous. Using the stock example above, inheriting saves $90,000 in taxable gain compared with receiving the same asset as a gift. Always verify whether the transfer occurred before or after death, because that single fact determines whether you use stepped up FMV or carryover basis.

How to Use Cost Basis Knowledge to Strategically Sell Inherited Assets

Knowing your correct basis lets you plan sales with confidence and avoid overpaying taxes. If your stepped up basis equals or exceeds the current market value, you can sell immediately with little or no taxable gain. If you expect the asset to appreciate further, delay the sale and make strategic improvements that increase basis before selling.

Timing improvements correctly matters. Capital improvements made after you inherit increase your adjusted basis and reduce your taxable gain. Document every qualifying improvement with invoices dated after the date of death, and keep a running tally so you know your adjusted basis at any moment. Verify FMV using the strongest available evidence. Professional appraisals for real estate, brokerage statements for securities. Do this before you list the property or execute the trade.

Sell soon after inheritance when stepped up basis equals or nearly equals sale price to minimize or eliminate capital gains tax.

Document all improvements with dated invoices to ensure you can add every dollar of qualifying expenditure to your adjusted basis.

Verify FMV with professional appraisals or brokerage statements dated at the date of death to substantiate your basis before filing Form 8949.

Avoid common mistakes such as using the decedent’s original purchase price, treating the sale as short term, or forgetting to adjust for improvements and depreciation.

Prepare for IRS substantiation by organizing death certificates, appraisals, Form 706 (if filed), broker statements, improvement invoices, and depreciation schedules in a single file you can produce on request.

Report every sale on Form 8949 and Schedule D, entering the date acquired as the date of death and checking the long term box. Attach explanatory statements if the 1099-B cost basis differs from your stepped up FMV basis. Keep all supporting documents for at least three years after filing the return reporting the sale, and longer if the asset was high value or the basis determination was complex.

Final Words

Start with the rule: cost basis = fair market value at date of death (or the six‑month alternate date). Use that number on Form 8949 and Schedule D so your gain is reported correctly.

Gather FMV docs (appraisals, broker statements, Form 706), note improvements or depreciation adjustments, and remember inherited assets are treated as long‑term.

If you’re ready, follow the checklist and build a simple basis worksheet to learn how to determine cost basis for inherited assets before selling. You’ll feel more confident and likely keep more of your gains.

FAQ

Q: How do I calculate the cost basis for inherited property?

A: The cost basis for inherited property equals the fair market value (FMV) on the decedent’s date of death, or the six‑month alternate valuation if elected on Form 706; use appraisals, broker statements, or probate values.

Q: How does IRS verify cost basis?

A: The IRS verifies cost basis by comparing your reported basis and supporting documents to third‑party records such as broker statements, Form 706 values, appraisals, and 1099‑B; mismatches can trigger notices.

Q: Do you have to pay capital gains on inherited property that you sell?

A: You pay capital gains on inherited property only if the sale price exceeds the stepped‑up basis (FMV at death plus allowable adjustments); inherited assets are treated as long‑term for tax rates.

Q: What is the step up cost basis for inherited property?

A: The step‑up cost basis for inherited property is raising the asset’s basis to its FMV on the decedent’s date of death, which typically lowers taxable gain when the beneficiary sells.