Tested tool guide
Tested browser tools
Checked August 16, 2026
What 1031 Exchange Calculator does, with a checked example
This calculator runs a real estate like-kind exchange through the IRS boot mechanics: enter the relinquished property's sale price, adjusted basis, and mortgage balance, then the replacement property's purchase price and new financing. It computes realized gain, any cash or mortgage boot, the portion of gain you must recognize this year, and the portion deferred into your new basis. The detail most people miss: buying a replacement property for less than the sale price, or paying down debt without adding offsetting cash, creates taxable boot even when no cash actually lands in your pocket.
Worked example
A concrete input and expected output from the current implementation.
Input
Relinquished property: sale price $500,000, adjusted basis $300,000, no existing mortgage. Replacement property: purchase price $450,000, paid all cash, no new loan. Combined federal + state capital gains rate: 20%.
->
Expected output
Realized gain: $200,000. Cash boot (proceeds not reinvested): $50,000. Recognized (currently taxable) gain: $50,000, taxed at $10,000. Deferred gain: $150,000, carried into the replacement property's basis, deferring $30,000 of tax.
Recognized gain is capped at the lesser of realized gain ($200,000) or boot ($50,000); because the replacement property cost $50,000 less than the sale price, that shortfall is boot and becomes immediately taxable, while the rest of the gain defers.