1031 Exchange Calculator: How to Estimate Your Tax Savings

Why a back-of-napkin estimate isn't enough

Most investors hear "capital gains tax" and multiply their gain by 15% or 20%. That captures one of four tax layers. A California investor selling a property with significant depreciation could face an effective rate above 35% when you stack federal capital gains, depreciation recapture at a maximum federal rate of 25%, the 3.8% net investment income tax, and state income tax.

The difference between a rough estimate and an accurate one can be $40,000-$80,000 on a typical exchange. That gap matters when you're deciding whether an exchange is worth the effort and constraints.

The four tax layers

Every investment property sale triggers up to four distinct taxes:

A 1031 exchange defers all four. That's why the total savings are almost always larger than investors expect.

How to calculate your adjusted basis

Your adjusted basis is what the IRS considers your "investment" in the property. It determines how much gain you have.

Start with your original purchase price. Add capital improvements - anything that adds value, extends the property's life, or adapts it to a new use. Roof replacements, kitchen renovations, HVAC systems, additions. Routine repairs and maintenance don't count.

Then subtract accumulated depreciation. For residential rental property, the IRS requires straight-line depreciation over 27.5 years. For commercial property, it's 39 years. Even if you never claimed depreciation on your tax returns, the IRS treats it as if you did.

Adjusted basis = Purchase price + Capital improvements - Accumulated depreciation

Example (simplified): You bought a rental for $400,000 (with $80,000 allocated to land, which isn't depreciable). You've owned it for 12 years and put $35,000 into a new roof and updated electrical partway through ownership.

• Depreciable basis: $320,000 (original building) + $35,000 (improvements) = $355,000
• Total depreciation over 12 years: ~$154,909 (simplified; in practice, each improvement starts its own depreciation schedule from its placed-in-service date - your CPA will calculate the precise figure)
• Adjusted basis: $400,000 + $35,000 - $154,909 = $280,091

If you sell for $650,000 with $39,000 in selling costs, your realized gain is $610,000 - $280,091 = $330,909. Of that, $154,909 is depreciation recapture (taxed at a maximum 25% rate) and $176,000 is capital gain (taxed at your capital gains rate).

Walking through a real calculation

Let's use the numbers above. The investor is married filing jointly with $180,000 in other taxable income, living in Colorado (4.4% flat state tax). Their MAGI for the year of sale will be approximately $510,909 ($180,000 + $330,909 gain).

*NIIT applies to the lesser of net investment income ($330,909) or the amount by which MAGI exceeds the $250,000 MFJ threshold ($510,909 - $250,000 = $260,909). The lower figure applies. Note: state tax estimates use top marginal rates as approximations and may vary based on your specific situation.

With a 1031 exchange, that ~$89,600 stays invested. At 6% annual returns, it grows to ~$160,000 in 10 years.

You can run this calculation with your own numbers in about 60 seconds using our 1031 exchange calculator. It handles all four tax layers, supports all 50 states, and requires no email or signup.

Common mistakes in 1031 tax estimates

Forgetting depreciation recapture. This is the most expensive mistake. Investors calculate their capital gain but ignore the up to 25% recapture tax on depreciation. On a property held for 15+ years, recapture alone can be $30,000-$80,000.

Using the wrong capital gains rate. The 20% rate only applies to taxable income above $613,700 (married filing jointly, per IRS 2026 inflation adjustments). Most investors fall into the 15% bracket. Some retirees selling a modest rental may even qualify for the 0% rate.

Ignoring state tax. Nine states have no income tax. California taxes capital gains as ordinary income at rates up to 13.3%. New York, New Jersey, and Oregon all exceed 9%. For a $300,000 gain, the state tax difference between Texas and California is roughly $40,000.

Not accounting for depreciation you should have claimed. The IRS applies "allowed or allowable" depreciation. If you owned a rental for 15 years and never claimed depreciation, the IRS still reduces your basis as if you had. You lose the deductions AND get taxed on the recapture.

Confusing equity with gain. Your gain is not the same as your equity. If you bought for $400,000 with a $300,000 mortgage and the property is now worth $600,000, your equity is $300,000 (after paying off the mortgage), but your gain could be $250,000+ after depreciation.

Basic vs. advanced calculations

A basic calculation uses your purchase price, sale price, depreciation, filing status, income, and state. That handles the majority of situations.

An advanced calculation adds: capital improvements, selling costs broken out as a dollar amount or percentage, current mortgage balance (relevant for boot calculations), property type distinctions (residential vs. commercial depreciation schedules), and mixed-use property allocations.

Our calculator offers both modes. Start with basic. Switch to advanced if you've made significant improvements or want to model different sale prices.

What to do with your number

Once you have your estimated tax liability, the decision framework is straightforward:

Under $25,000 in tax: The exchange may not be worth the constraints and execution risk. Consider whether the 45-day deadline pressure and the requirement to stay in real estate justify the savings.

$25,000 - $75,000: Worth serious consideration. The savings are meaningful, but weigh them against your desire to stay in real estate and your ability to find replacement property quickly.

Over $75,000: Very likely worth pursuing if you want to remain in real estate. The compounding benefit over 10-20 years is substantial.

Whatever your number, share it with your CPA. The calculator provides an estimate - your tax professional can refine it with your complete tax picture.