U.S. · Tax forms
Form 8824 line 18, basis of what you gave up.
Adjusted basis, leftover exchange expenses and net amounts you paid, added up the way the IRS lists them.
Line 18 is the sum of three things: the adjusted basis of the like-kind real property you gave up, your exchange expenses that were not used to reduce line 15, and the net amount you paid to the other party. Subtracting line 18 from line 17 gives the realized gain or loss on line 19.
Look up a piece
Result
The three pieces of line 18
| Item | Meaning | What the IRS says |
|---|---|---|
| Adjusted basis | Like-kind property given up | The adjusted basis of the like-kind real property you gave up. |
| Exchange expenses | Only the part not used on line 15 | Exchange expenses, if any (except for expenses used to reduce the amount reported on line 15). |
| Net amount paid | Excess you paid to the other party | The excess, if any, of the total of (a) any liabilities you assumed, (b) cash you paid to the other party, and (c) the FMV of the other (non-like-kind) property you gave up over any liabilities assumed by the other party. |
| Line 15 link | Expenses are used once | Line 15 is reduced (but not below zero) by exchange expenses you incurred; only expenses not used on line 15 are added on line 18. |
| Line 19 | What line 18 feeds | Realized gain or (loss): subtract line 18 from line 17. |
How to build line 18
Start with the adjusted basis of the like-kind real property you gave up. Add any exchange expenses you did not use to reduce line 15. Then add the net amount you paid to the other party, which is the excess of what you handed over (liabilities you assumed, cash you paid and the FMV of non-like-kind property you gave up) over the liabilities the other party assumed.
Exchange expenses count once
Exchange expenses reduce line 15 first (but not below zero). Only the amount not used there is added on line 18, so the same expense is not counted on both lines.
Related lines
Line 15 and line 16 are the “received” side that line 18 is compared with on lines 17 and 19. Line 25 later uses line 18 again: basis of the like-kind property received is the sum of lines 18 and 23 less line 15.
Worked example
IRS example, Taylor. Taylor’s apartment building had an adjusted basis of $100,000. Taylor assumed Finley’s $150,000 mortgage while Finley assumed Taylor’s $80,000 mortgage, a $70,000 excess ($150,000 − $80,000). Taylor enters $170,000 on line 18 ($100,000 + $70,000). IRS example, Finley. Finley enters only the adjusted basis of $175,000, because the $80,000 of liabilities Finley assumed plus the $40,000 cash paid does not exceed the $150,000 of liabilities assumed by Taylor. All figures are the IRS’s own example.
More line pages in this set
Related lines: Form 8824 Line 15, Form 8824 Line 16, Form 8824 Line 25a.
Sources
- Instructions for Form 8824 (2025): the line-by-line instructions on this page. Page last reviewed or updated April 30, 2026. Read November 2, 2026.
- Form 8824 (Like-Kind Exchanges): the printed line wording and arithmetic on the form. Read November 2, 2026.
Instructions for Form 8824, 2025 edition. The line labels were read from the Form 8824 (2025) PDF the IRS had posted on the date read. Line numbers can shift between years, so check them against the form for your tax year. Examples marked made-up use invented figures; the others reproduce the IRS’s own examples.
Frequently asked questions
What goes on Form 8824 line 18?
The sum of the adjusted basis of the like-kind real property you gave up, exchange expenses not used on line 15, and the net amount you paid to the other party.
What is the net amount paid to the other party?
The excess, if any, of liabilities you assumed, cash you paid and the FMV of other (non-like-kind) property you gave up, over any liabilities the other party assumed.
Where do exchange expenses go?
They first reduce line 15 (but not below zero). Expenses not used on line 15 are added on line 18.
What was line 18 in the IRS example?
Taylor entered $170,000 (the $100,000 adjusted basis plus a $70,000 excess of liabilities assumed). Finley entered $175,000, only the adjusted basis.
What does line 18 feed?
Line 19, realized gain or loss, is line 17 minus line 18. Line 18 is also used in the line 25 basis computation.
Not tax advice
This page summarizes IRS instructions, mostly written for the people who prepare the form, and is not tax, legal or financial advice. A CPA or an enrolled agent can confirm what a line means for your return. Everything runs in your browser; nothing you enter is sent anywhere.