Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Taxable boot (recognized gain)
$70,000
Gain deferred
$140,000
New basis in replacement property
$340,000
Total boot (cash + debt relief)
$70,000
Realized gain on sale
$210,000
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter relinquished property sale price ($).
- 2Enter selling costs ($).
- 3Enter adjusted basis of relinquished property ($).
- 4Enter old mortgage payoff ($).
- 5Enter replacement property purchase price ($).
- 6Enter new mortgage on replacement ($).
- 7Enter cash taken out (not reinvested) ($).
- 8Read your taxable boot (recognized gain) on the right — it updates as you type.
- 9Hit Share to keep the scenario or send it to someone.
About this calculator
A 1031 exchange defers capital gains tax only to the extent you reinvest all net proceeds into equal-or-greater value replacement property with equal-or-greater debt. Any shortfall — cash you pocket or debt relief you don't replace — is boot, and boot is taxed in the year of the exchange even though the rest of the gain is deferred. This calculator takes your relinquished property's sale price, selling costs, original basis, and the replacement property's purchase price and debt, and computes both cash boot and debt-relief boot, plus your new basis in the replacement property. New basis rolls forward: it's replacement cost minus the deferred gain, or equivalently your old adjusted basis plus any additional cash you put in, minus any boot received. Getting this wrong is the most common reason investors get an unpleasant tax bill despite thinking they'd fully deferred everything, because they forgot that paying down more debt than you replace also counts as boot.
Worked example
Using the values the calculator loads with:
Inputs
- Relinquished property sale price: 500000 $
- Selling costs: 30000 $
- Adjusted basis of relinquished property: 260000 $
- Old mortgage payoff: 200000 $
- Replacement property purchase price: 480000 $
- New mortgage on replacement: 150000 $
- Cash taken out (not reinvested): 20000 $
Results
- Taxable boot (recognized gain): $70,000
- Gain deferred: $140,000
- New basis in replacement property: $340,000
- Total boot (cash + debt relief): $70,000
- Realized gain on sale: $210,000
What each field means
Inputs
- Relinquished property sale price ($)
- The relinquished property sale price used in the calculation, measured in $. Starts at 500000 $ so you have a working example on load.
- Selling costs ($)
- The selling costs used in the calculation, measured in $. Starts at 30000 $ so you have a working example on load.
- Adjusted basis of relinquished property ($)
- The adjusted basis of relinquished property used in the calculation, measured in $. Starts at 260000 $ so you have a working example on load.
- Old mortgage payoff ($)
- The old mortgage payoff used in the calculation, measured in $. Starts at 200000 $ so you have a working example on load.
- Replacement property purchase price ($)
- The replacement property purchase price used in the calculation, measured in $. Starts at 480000 $ so you have a working example on load.
- New mortgage on replacement ($)
- The new mortgage on replacement used in the calculation, measured in $. Starts at 150000 $ so you have a working example on load.
- Cash taken out (not reinvested) ($)
- The cash taken out (not reinvested) used in the calculation, measured in $. Starts at 20000 $ so you have a working example on load.
Results
- Taxable boot (recognized gain)
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Gain deferred
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- New basis in replacement property
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total boot (cash + debt relief)
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Realized gain on sale
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
What exactly counts as boot?
Any non-like-kind value you receive: cash pocketed at closing, personal property thrown in, or 'debt relief' — meaning you paid off more mortgage debt than you took on in the new purchase. Even if you never touch that debt-relief cash, the IRS treats it as boot because your net equity position improved relative to like-kind debt.
How do I avoid debt boot without extra cash?
Match or exceed your old loan balance with new debt, or add outside cash to the deal to make up the gap. Many investors deliberately take on slightly more replacement debt than the old payoff specifically to zero out debt boot.
Does this calculator replace a qualified intermediary?
No. This gives you a planning estimate. A qualified intermediary and your CPA handle the actual exchange documents, 45-day identification, and 180-day closing deadlines, and they'll run exact numbers off closing statements.
What happens to depreciation recapture in a 1031?
Section 1250 depreciation recapture is deferred along with the capital gain as long as no boot is recognized on that portion. If boot is present, recapture is generally recognized first, up to the amount of boot, before any capital gain portion is taxed.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Depreciation Recapture on Sale Calculator
Split your sale gain into recapture tax and long-term capital gains tax.
Cost Segregation First-Year Benefit Calculator
Estimate accelerated depreciation and first-year tax savings from a cost seg study.
Seller Financing Note Yield Calculator
Calculate the effective yield a seller earns carrying a note, including any discount.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). 1031 Exchange Boot and Basis Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/1031-exchange-boot-basis
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/1031-exchange-boot-basis" target="_blank" rel="noopener">1031 Exchange Boot and Basis Calculator — RevenueLab</a> (2026).</p>
Source: [1031 Exchange Boot and Basis Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/1031-exchange-boot-basis) (2026).