Boot in one sentence
Boot is anything you receive in a 1031 exchange that is not like-kind property, and it is taxable up to the amount of your realized gain. That is the whole definition. The complications come from how many things quietly count as receiving something.
Investors expect cash to count. What surprises them is that carrying a smaller mortgage on the new property counts too, even though no money changes hands. So does buying a cheaper replacement, and so does having the exchange pay off a personal loan at closing. Each one is the IRS noticing you walked away better off in a way that has nothing to do with owning real estate.
Boot does not break an exchange. A partial exchange is perfectly valid: you pay tax on the boot and defer the rest. The unwelcome part is that boot is taxed at the worst available rate, because the taxable slice is characterized as depreciation recapture first.
The exchange we will work through
An investor sells a rental for $900,000 with $54,000 of selling costs, so the net sale price is $846,000. The property was bought for $500,000, improved by $50,000, and depreciated by $100,000. Adjusted basis is $500,000 plus $50,000 minus $100,000, which is $450,000.
Realized gain is the $846,000 net minus the $450,000 basis, which is $396,000. That is the ceiling on what any boot can be taxed on. The property was owned free and clear, so no mortgage complicates the first version of the story.
The plan is to exchange into a $1,000,000 replacement. If all $846,000 of net proceeds passes through the qualified intermediary into the purchase, the entire $396,000 gain defers and nothing is taxable today. Now watch what one decision does to that.
Cash boot: $50,000 out, $14,400 owed
The investor decides to keep $50,000 at closing. Maybe for reserves, maybe for a kitchen at another property, maybe just because it is a lot of money sitting right there. The intermediary receives $796,000 instead of $846,000, and the $50,000 is cash boot.
That $50,000 is taxable now, and not at the capital gains rate the investor was imagining, because boot is characterized as unrecaptured Section 1250 gain first. With $100,000 of prior depreciation available to absorb it, the entire $50,000 is recapture, taxed at 25% for $12,500. Add the 3.8% net investment income tax on the same $50,000, which is $1,900. Tax due this year: $14,400.
Effective rate on that withdrawal: 28.8%. The investor keeps $35,600 of the $50,000 they pulled off the table. Whether that is worth it depends on what the cash is for, but it should be a decision, not a discovery in April.
- Cash boot received: $50,000
- Recapture at 25%: $12,500
- Net investment income tax at 3.8%: $1,900
- Tax due now: $14,400, leaving $35,600 in hand
What the withdrawal did to the rest of the deal
Two things change beyond the immediate bill. Deferred gain drops: the $396,000 realized gain minus the $50,000 recognized as boot leaves $346,000 riding into the replacement property.
And the basis in the new property is not what you paid for it. Carryover basis is the $1,000,000 purchase price minus the $346,000 of deferred gain, which is $654,000. That is the number future depreciation is computed on, and it is why exchanging repeatedly produces buildings with large price tags and small deductions. The mechanics of that annual figure are in rental property depreciation explained.
For scale, compare the paths. Selling outright would have produced a federal bill of about $99,248 across recapture, capital gains, and the net investment income tax. The exchange with $50,000 of boot costs $14,400 today. The difference, $84,848, is postponed rather than forgiven, and postponed money is money you get to use. Run both versions side by side in the 1031 exchange calculator.
Mortgage boot: the one with no cash involved
This is the version that ambushes people, so here is a separate scenario with clean numbers. Sell a property for $900,000 that carries a $400,000 mortgage, and buy a $1,000,000 replacement with only a $300,000 new loan. No cash left the exchange. Every dollar of proceeds went into the purchase. And $100,000 of boot exists anyway, because debt relief is treated as value received.
The logic is consistent once you see it. Somebody else took over $400,000 of obligation you had, and you picked up only $300,000 of new obligation. You are $100,000 better off in a way that is not real estate.
The fix has two forms: carry equal or greater debt on the replacement, or bring outside cash to closing to cover the shortfall. What does not work is netting in the direction you would prefer, because cash you take out cannot be offset by taking on extra debt. If you are reshaping the loan anyway, size it in the refinance calculator before you decide, since the loan amount is now a tax decision and not only a payment decision.
Buying down in price
The third source is the simplest. Trade down and the difference is boot. Sell for $846,000 net and buy for $700,000, and roughly $146,000 of value never made it into like-kind property, so it is taxable up to your realized gain. The intermediary hands the leftover funds back at the end of the exchange period and the IRS treats them exactly as if you had pocketed them at closing.
This is why investors sometimes buy a property they only half want, or split into two replacements to soak up the remainder. Those are real strategies with real risks. If the candidates are all mediocre, underwriting them honestly in the rental property calculator and choosing to pay tax on a partial exchange is a legitimate answer. The tax tail wagging the investment dog costs more than the tax.
The two rules that avoid boot entirely
Everything above collapses into two requirements. Reinvest all of the net proceeds, meaning every dollar the intermediary holds goes into the replacement. And take on debt equal to or greater than the debt you paid off, or make up the difference with cash from outside the exchange. Meet both and there is no boot.
A shorter way to hold it: the replacement should cost at least as much as the net sale price, and your equity in it should be at least as large as your equity was. Both halves matter. Investors who watch only the price sometimes hit the target with a much smaller loan and get billed for the gap.
Here is the one I got wrong. On my first exchange I assumed I could take my original down payment back out at closing without consequence, because in my head that was my own money going in, not gain coming out. Boot does not care which dollars you believe you are withdrawing. Cash out is taxed to the extent of gain, and the gain in that deal was far larger than the withdrawal I had planned, so all of it would have been taxable. My intermediary caught it. That conversation was worth more than his fee.
- Rule one: reinvest 100% of the net proceeds from the sale.
- Rule two: match or exceed the old debt, or cover the gap with outside cash.
- Watch out: cash boot cannot be offset by taking on extra debt.
- Watch out: paying personal debts or non-transaction costs from exchange funds creates boot.
If you actually need the cash
Sometimes you need money and no amount of structuring changes that. The first option is exactly what the example does: take the boot, pay the $14,400, defer the other $346,000 knowingly. Nothing is wrong with a partial exchange as long as it is chosen.
The second is refinancing rather than withdrawing, and this one needs care. Pulling cash out of the relinquished property shortly before the exchange can be recharacterized as boot, since the effect matches taking cash at closing. Refinancing the replacement after the exchange is complete is the more commonly used path. Both are fact-specific and both belong in front of your advisors before you file a loan application.
Which is the right place for the standing caveat. All of this is arithmetic on the stated figures, not tax advice. Rates, brackets, state taxes, and your entity structure move the result, so confirm every number with a CPA before you sign the exchange documents.
Questions people ask
Anything you receive that is not like-kind property, taxable up to the amount of your realized gain. The common forms are cash taken at closing, debt relief when the new mortgage is smaller than the old one, and buying a replacement that costs less than the net sale price.
In the worked example, $14,400. Boot is characterized as unrecaptured Section 1250 gain first, so the $50,000 is taxed at the 25% recapture rate for $12,500, plus 3.8% net investment income tax for $1,900. That is an effective rate of 28.8% on the withdrawal.
Yes. If the debt you pay off exceeds the debt you take on, the difference is treated as value received. Paying off a $400,000 loan and borrowing only $300,000 creates $100,000 of boot. Offset it by borrowing more or bringing outside cash to the closing.
No. A partial exchange is valid. You recognize gain only up to the boot received and defer the rest. In the example, $50,000 is taxed now and $346,000 stays deferred, carrying into a $654,000 basis on the $1,000,000 replacement.
Reinvest all of the net proceeds and carry debt equal to or greater than what you paid off, covering any shortfall with cash from outside the exchange. In practice that means buying a replacement worth at least the net sale price while keeping your equity at least as large as before.
