1031 Exchange Calculator: Estimate Your Gain
For U.S. property, this like-kind exchange calculator shows gain counted now vs. deferred, after confirmed ordinary recapture, debt relief and cash boot.
What This Calculator Does
This ledger sets the gain you recognize now beside the gain you defer in a single qualifying 1031 swap of U.S. real property. Enter the documented prices and debt, eligible costs for the sale and the purchase, and your full adjusted basis, plus ordinary recapture already figured for Form 8824, line 21. You'll see how boot and that recapture interact. It won't compute the tax you owe, and it doesn't rule on eligibility.
Who Is This For
Bring whatever you get here to your qualified intermediary and tax adviser, since the tool is meant for property investors and people who work in real estate. It reads every figure as belonging to a single taxpayer and a single ownership interest. Co-owners or several assets? Then it can't split the swap for you. Money moves in a fixed order: exchange equity pays toward the replacement first, and your own cash only tops up what's missing. A separate cash withdrawal paired with a personal contribution is the case the model leaves out. You won't get Form 8824 from it, and it doesn't establish the replacement property's basis.
How It Works
The form takes eight amounts, all in dollars; put 0 in any that doesn't apply to you. Eligible selling costs get their own box, apart from eligible costs of buying the replacement. For basis, enter your full adjusted basis. Ordinary recapture comes in from a line 21 calculation done elsewhere. Enter 0 there only after you've confirmed there is none. Then hit calculate. Before exporting anything, look over gain, boot and recapture.
Frequently Asked Questions
Will my tax bill equal the recognized gain?
No. The calculator takes your sale price, strips out eligible costs on both ends of the deal, then removes your complete adjusted basis, and that leaves realized gain. Of that, the modeled rules count part now: your recognized gain. Positive gain still left over is deferred. Rates aren't applied. Neither NIIT nor state tax is calculated, and withholding isn't either. The character of the leftover gain isn't worked out. So a 0 in the recognized column is not evidence of a zero tax bill.
Which property counts, and which deadlines matter most?
Check the property before the calendar. Real property you keep as an investment, or put to work in your trade or business, is what Section 1031 generally covers, as long as it qualifies and is like-kind. A personal residence isn't something this estimator handles. Neither is property you hold mostly to sell. In a deferred swap, you generally have 45 days to identify the replacement, and you generally must receive it within 180 days or by your tax-return due date with extensions, whichever comes sooner. Your qualified intermediary and tax adviser need to confirm the property, the structure, those deadlines and the fund-receipt rules. A number on this page is not a green light.
Does a paid-off mortgage lower gain, and what makes up basis?
No, not the gain. Principal you've paid down moves your equity and feeds the debt-relief math, while realized gain stays where it was. Basis comes from your own records, and it's the full adjusted tax basis. Picture a running total: the applicable original basis, eligible costs you paid when you bought, capital improvements, then minus required reductions like depreciation allowed or allowable. So the old purchase price alone won't do. If depreciation is already out of your basis, don't take it out again. Costs from the original purchase go into that basis where they apply. Costs of buying the replacement in this swap have a field of their own.
Why enter costs for both the sale and purchase?
Because costs on each side can shrink your result. The model lets confirmed eligible costs of selling and of buying the replacement reduce realized gain, and lets those same costs offset cash boot. That follows IRS Publication 544, which ties eligible exchange expenses to the property you relinquish and the property you acquire. Your intermediary or adviser decides, charge by charge, what counts; a closing statement can't settle it alone. Leave out tax and rent prorations. Deposits, repairs and loan expenses stay out too. An acquisition charge belongs in a single spot: expenses, or price, or basis. What you see for equity and net cash boot is a tax-ledger number. It isn't your escrow balance or the closing wire.
How does the tool figure cash and debt-relief boot?
Anything you get that isn't like-kind property counts as boot, and the tool measures it by net cash and by net debt relief. On the cash side, your equity after all eligible costs is set against the part of the replacement price paid with equity. Exchange equity is spent on the replacement first. Your own cash only fills a shortfall. Put in extra cash and you can offset debt relief. Take on extra debt, though, and cash boot stays put. The tool also assumes the old loan is repaid completely, without forgiveness, and that the new loan is no larger than the replacement price. A separate cash withdrawal paired with a personal contribution needs review outside the model. So does any other tangled money flow.
Why doesn't ordinary recapture stack on top of the boot limit?
Because recapture gets counted before anything else. Start with the line 21 ordinary recapture; subtract that amount from the boot-limited gain, and whatever remains above 0 is the rest of your recognized gain. Take a swap with no costs: you sell for $220,000 with a basis of $100,000 and old debt of $80,000. The replacement costs $250,000, with new debt of $150,000. Realized gain comes to $120,000, and boot to $40,000. Now add ordinary recapture of $50,000, determined outside the tool. Total recognized gain is $50,000, not $90,000, and $70,000 stays deferred. Accumulated depreciation can't stand in for ordinary recapture, and neither can unrecaptured Section 1250 gain.
What if the swap falls through or I lose money?
Without a replacement, any positive gain is recognized in full. To model that, enter 0 as the replacement price on purpose, and the tool treats it as a swap that never finished. A loss is different. It stays negative, this 1031 estimate recognizes none of it, and with a realized loss the deferred gain reads 0. That doesn't prove you have a deductible loss, a refund or a tax credit coming. Where there's no positive gain, recapture is 0 too. Your tax adviser settles how a failed swap or a loss is treated, outside the tool.
What must a pro work out separately?
Start with eligibility, which a professional settles along with your complete adjusted basis, which expenses count and the amount for Form 8824, line 21. The tool skips allocation across several assets and never computes replacement basis. Section 121 combined with 1031? Not modeled. Installment sales and related-party rules aren't handled either. Your closing statements and financing belong in front of your qualified intermediary and tax adviser. For reference, the IRS Publication 544 and Form 8824 instructions used here are the 2025 editions, and sources were checked October 2, 2026, against rules as of September 30, 2026.