A 1031 exchange calculator helps investors compare tax-deferred exchange scenarios against a taxable sale using estimated gains, exchange costs, and replacement property basis. Use it for education and planning, then confirm details with a qualified intermediary and tax professional.
Explore more real estate planning tools under mortgage and real estate, finance calculators, and the calculators archive. This page is for investment property exchanges. Primary residence exclusion math belongs on the capital gains on home sale calculator, and keep-versus-rent decisions belong on the rent vs sell calculator.
What this 1031 exchange calculator does
The tool acts as a like kind exchange calculator and a deferred gain calculator for educational planning. Enter the relinquished sale price, basis, selling costs, mortgages, replacement price, and any cash you take out. You get realized gain, estimated boot, approximate tax on boot, and deferred gain. It is a 1031 exchange tax calculator sketch, not legal or tax advice and not a substitute for a qualified intermediary.
Who it helps
- Investors comparing full deferral versus partial cash-out scenarios
- Owners checking whether replacement equity is high enough to avoid boot
- Advisors building a first-pass deferred gain estimate before deeper modeling
- Anyone who wants a free online estimate without creating an account
How to model a like-kind exchange scenario
- Enter the relinquished property sale price, adjusted basis, and selling costs.
- Enter the old mortgage balance and the replacement purchase price and new mortgage.
- Enter any cash out you expect to receive and a planning tax rate for boot.
- Review realized gain, taxable boot, tax on boot, and deferred gain.
- Adjust replacement price or mortgages until boot falls to the level you can accept.
How the calculation works
Realized gain equals sale price minus basis minus selling costs. Boot combines cash out, mortgage boot when the old loan exceeds the new loan, and any equity shortfall when you do not reinvest enough equity into the replacement. Deferred gain equals realized gain minus boot, floored at zero. Boot itself is capped at the realized gain in this Multicalify model.
Gain = sale – basis – selling costs
Boot ≈ cash out + mortgage boot + equity shortfall (capped at gain)
Deferred gain = gain – boot
Mortgage boot is the positive amount of old mortgage minus new mortgage. Equity on the old side is sale minus old mortgage minus selling costs. New equity is replacement price minus new mortgage. An equity shortfall appears when old equity exceeds new equity after accounting for cash out. This is a simplified classroom-style map. Deadlines, identification rules, and QI procedures are outside the form.
Worked example
Sell an investment property for $600,000 with a $350,000 basis and $36,000 selling costs. Realized gain is $214,000. Buy a $700,000 replacement with enough new financing and equity so cash out and mortgage boot are zero. Estimated boot is $0 and deferred gain is $214,000 under this simplified path. If you take cash out or reduce mortgage balance without replacing equity, boot rises and deferred gain falls.
| Item | Value |
|---|---|
| Sale price | $600,000 |
| Basis | $350,000 |
| Selling costs | $36,000 |
| Realized gain | $214,000 |
| Replacement price (enough equity) | $700,000 |
| Estimated boot | $0 |
| Deferred gain | $214,000 |
How to interpret deferred gain and boot
Deferred gain is the portion of realized gain you are modeling as postponed, not erased. Boot is the portion treated as currently taxable in this estimate. A zero-boot case still requires strict timing, property qualification, and QI handling in a real exchange. A partial boot case can still be useful when you need some liquidity and accept current tax on that slice.
Do not confuse this tool with primary residence Section 121 planning. If you are selling a home you lived in, start with the capital gains on home sale calculator. If you are choosing between renting and selling an owned house without an exchange, use the rent vs sell calculator. For return framing on replacement property cash flow, the ROI calculator can help after the exchange structure is clear.
Factors that change boot
- Cash taken out at closing or during the exchange
- Dropping mortgage debt without replacing equivalent debt or equity
- Buying a cheaper replacement that cannot absorb relinquished equity
- Selling costs that raise realized gain while reducing net equity
- Replacement price and loan size relative to the old property
- Tax rate assumptions used only to sketch tax on boot
Practical exchange planning tips
Build the replacement target first: equal or greater value and equal or greater equity is the usual educational rule of thumb for aiming at full deferral. Then stress-test a cash-out case so you see the tax trade-off explicitly. Keep selling cost estimates realistic by reviewing local commission and closing friction with the closing costs calculator.
Engage a qualified intermediary and a tax professional before you sign a sale contract that must qualify. Identification windows and receipt rules are strict. This calculator cannot validate QI contracts, related-party limits, or whether a property is like-kind under current law.
Mistakes that break 1031 timing or identification rules
- Treating deferred gain as permanently tax-free
- Using a primary residence capital gains page for investment exchange math
- Ignoring mortgage boot when the new loan is smaller than the old loan
- Underfunding replacement equity and discovering boot too late
- Skipping QI and deadline planning because the spreadsheet looks clean
- Assuming the educational tax-on-boot figure matches your final return
Limitations and YMYL note
This 1031 exchange calculator is a simplified educational estimate, not tax, legal, or exchange advice. It does not guarantee deferral, qualify properties, or replace a qualified intermediary and licensed tax professional. Real exchanges involve IRS rules, state considerations, and documentation this form does not cover. Confirm every number before you close.
Related tools
Use the capital gains on home sale calculator for residence exclusion sketches, the rent vs sell calculator for hold-versus-list choices, the ROI calculator for return ratios, and the closing costs calculator for friction estimates. More tools sit under mortgage and real estate.
Why replacement equity matters as much as price
A higher replacement price alone does not always eliminate boot. If the new mortgage is structured so your equity into the deal is lower than the equity you extracted from the old property, the model can still show an equity shortfall. That is why Multicalify surfaces boot components instead of only celebrating a larger purchase price.
When you compare two replacement candidates, hold sale-side inputs fixed and change only replacement price, new mortgage, and cash out. The deferred gain swing tells you which structure better supports your deferral goal under this simplified lens.
Cash-out versus full deferral trade-offs
Taking cash out can fund reserves, repairs, or diversification, but it usually creates taxable boot in this framework. Run the zero cash-out case and a deliberate cash-out case side by side. Decide whether the liquidity is worth the estimated current tax before you instruct the QI and closing teams.
Remember that deferred gain remains attached to the replacement basis story. Future sales can recognize what you postponed. Plan exit strategy with the same seriousness as the inbound exchange.
When a 1031 model is worth running
Run the calculator when you are comparing a taxable sale with an exchange path using the same property assumptions. Keep qualified intermediary fees and timelines outside the spreadsheet fantasy, and treat every output as an estimate rather than a filing position.
Boot, basis, and why replacement value matters
Cash boot and non-like-kind property can create taxable gain even when you complete an exchange. The calculator is for directional planning. Identification windows, related-party rules, and debt replacement requirements need professional review before you commit.
Related: Capital Gains Home Sale Calculator · Rent vs Sell Calculator.