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1031 exchange calculator
Sell one rental and buy another: the gain you defer, any taxable boot, the federal tax you put off, and the dates you cannot miss.
Gain deferred by the exchange
$0
Federal tax put off: about $0.
| Equity from the sale | $0 |
|---|---|
| Cash kept (cash boot) | $0 |
| Debt not replaced (mortgage boot) | $0 |
| Gain taxed now | $0 |
Deadlines
Under IRS Publication 544, Receipt requirement, you must receive the replacement by the earlier of day 180 after the sale or the due date (including extensions) of the return for the tax year of the sale. The calculator uses the filing deadline you enter; it does not obtain an extension or determine your filing deadline.
The tax estimate uses up to 25 % on the depreciation part of the gain and your rate on the rest; it leaves out the 3.8 % net investment income tax and state tax. A qualified intermediary must hold the sale money; if it touches your account, the exchange fails.
Three rules for a fully deferred exchange
- Buy equal or up: the replacement costs at least the net sale price.
- Reinvest all the equity: every dollar of sale proceeds goes into the new property.
- Replace the debt: take a new mortgage at least as large as the one paid off, or add your own cash to cover the difference.
Miss one and the shortfall is boot, taxed up to the amount of your gain.
Closing deadline
The calculator compares day 180 with the actual federal tax return due date you enter for the tax year of the sale, including any extension you have obtained. It displays the earlier date. Confirm that filing deadline with your tax professional; entity types, fiscal years and filing relief can differ. See the receipt requirement in IRS Publication 544.
Example
You sell for $500,000 with $30,000 of selling costs, so the amount realized is $470,000. Your adjusted basis is $250,000: the gain is $220,000. You pay off a $200,000 mortgage, leaving $270,000 of equity. You buy a $600,000 rental with all $270,000 and a $330,000 loan: no boot, the full $220,000 is deferred. Keep $50,000 of the cash instead and increase the new loan to $380,000 to fund the same purchase: that $50,000 is taxed now.
What carries over
The deferred gain lowers the basis of the new property, so its future depreciation is based on the old basis plus any extra you invested. The exchange is reported on Form 8824 with your return for the year of the sale.
Questions
What is a 1031 exchange?
A way to sell investment or business real estate and buy other real estate held for investment or business without paying tax on the gain now. The gain is deferred, not forgiven: it carries over into the new property. It is named after section 1031 of the Internal Revenue Code.
What are the 1031 exchange deadlines?
You must identify the replacement property in writing within 45 days after the sale closes, and receive it within 180 days, or by the due date of your tax return for that year (with extensions) if that comes first.
What is boot in a 1031 exchange?
Anything you get from the exchange that is not like-kind real estate: cash you keep, or debt relief when your new mortgage is smaller than the old one and you do not add cash to make up the difference. Boot is taxed, up to the amount of your gain.
Can I do a 1031 exchange on my home?
No. Both properties must be held for investment or for use in a business. A personal residence does not qualify, and since 2018 only real property qualifies.
Do I need a qualified intermediary?
In practice, yes. If you receive the sale money, even briefly, the exchange fails. A qualified intermediary holds the funds from the sale until they buy the replacement property for you.
Sources
Next steps
Last updated November 7, 2026.