How Section 179 Recapture on Disposition Works

Section 179 recapture is what happens when property you fully expensed in an earlier year stops earning that deduction: the IRS pulls back the difference between what you wrote off and what ordinary depreciation would have allowed, and taxes it as ordinary income in the year the problem shows up. The trigger is almost always the same — business use of the property drops to 50% or less, or you dispose of the property, before its MACRS recovery period ends.¹ You do not have to sell anything to owe the tax. The character of your original deduction simply changed, and the return has to catch up.

What Triggers Recapture

Section 179 property has to stay in qualified business use for its full recovery period, which for most equipment is five or seven years.² If business use falls to 50% or less in any year during that window, you have a recapture event for that year.³

The most common cause is drift. A delivery truck starts pulling weekend duty. A computer expensed for a home office turns into the family machine. Once the business-use percentage crosses the 50% line, the recapture rules kick in whether you sold the property or not.

Selling the property before the recovery period ends also forces a recapture analysis, as does trading it, gifting it, or donating it. An involuntary conversion — theft or casualty loss — can trigger recapture too, though reinvesting insurance proceeds into qualifying replacement property within the required timeframe can avoid it.

Recapture is always taxed as ordinary income. It cannot be converted into capital gain, no matter how the property leaves your hands.

One Situation That Does Not Trigger Recapture

Death of the owner generally does not cause Section 179 recapture. Property passing to an heir gets a stepped-up basis at fair market value on the date of death, which wipes out the prior depreciation history. The heir starts fresh and only faces recapture on depreciation they claim themselves.

How to Calculate What You Owe

The math compares your original Section 179 deduction against the depreciation you would have taken under standard MACRS if you had never made the election. The excess is the recapture amount.

Find the Section 179 deduction you claimed in the year the property was placed in service.
Compute the MACRS depreciation you would have been entitled to from that placed-in-service year through the year of the triggering event, as if you had used straight depreciation from the start.
Subtract the hypothetical MACRS total from your original Section 179 deduction. The remainder is ordinary income in the current year.

A Worked Example

A business buys a $50,000 piece of five-year MACRS property in 2023 and takes the full $50,000 as a Section 179 deduction. In 2025, business use falls to 40%. Five-year MACRS under the 200% declining balance method with a half-year convention gives 20% in year one, 32% in year two, and 19.2% in year three, so allowable depreciation through 2025 would have been $10,000 + $16,000 + $9,600 = $35,600.²

Recapture is $50,000 minus $35,600, or $14,400, reported as ordinary income on the 2025 return. The remaining $14,400 of basis can still be depreciated over what is left of the recovery period, but only at the 40% business-use rate, so the going-forward write-off is small.

Timing matters. The later the trigger falls in the recovery period, the less there is to recapture. By year three of a five-year asset, MACRS has already covered 71.2% of the cost. By year five, there is almost nothing left. The first two years carry the highest exposure.

Vehicles Are the High-Risk Case

Vehicles cause more Section 179 recapture problems than any other asset, because mixed personal and business use is hard to avoid. Most passenger vehicles are classified as listed property, which brings tighter documentation rules and a separate recapture framework under Section 280F.³

Business use for a vehicle is measured by dividing business miles by total miles for the year. The IRS expects a contemporaneous mileage log — kept weekly or at the time of each trip, not reconstructed at tax time — showing date, destination, business purpose, trip mileage, and odometer readings.⁴ Without the log, there is no defense if the 50% threshold is questioned. Vehicle deductions are one of the most common audit triggers for small businesses.

When recapture hits a vehicle, the hypothetical MACRS depreciation you compare against is itself capped by the annual passenger automobile limits. Because those caps kept the hypothetical deductions small in each year, the recapture amount often comes out larger than owners expect.

How to Report It on Your Return

Recapture is reported on Form 4797, but the part of the form you use depends on what triggered it. Getting this wrong is a common filing error.⁵

If you still own the property but business use dropped to 50% or below, the calculation goes in Part IV. The original Section 179 deduction goes on line 33, the hypothetical MACRS depreciation through the current year on line 34, and the difference on line 35.⁶ That line 35 amount is then reported as other income on the same schedule where the deduction was originally claimed: Schedule C, E, or F.³

If you sold, traded, or otherwise disposed of the property, the transaction goes through Part III of Form 4797, which handles depreciation recapture on dispositions. Any Section 179 amount is treated as prior depreciation allowed and is recaptured as ordinary income to the extent of gain, with the result flowing through line 31 to your main return.⁶

Form 4797 is required even when no sale occurred. A simple conversion from business to personal use still calls for the form.⁵

Passthrough Owners: Partners and S Corporation Shareholders

If a partnership or S corporation claimed the deduction, the recapture is computed at the entity level and passed through to owners on Schedule K-1. For S corporations, Box 17 uses Code K for dispositions of Section 179 property and Code L for recapture caused by business use dropping to 50% or below.⁷ Each owner then reports their allocated share on their personal Form 4797.

A trap worth flagging: your share of the recapture is based on your current ownership percentage, not your ownership when the property was placed in service. Buying into an S corporation after the fact can put you on the hook for recapture income tied to a deduction you never personally took.

What Happens If You Do Not Report It

Unreported recapture is an understatement of tax. The standard accuracy-related penalty is 20% of the underpayment.⁸ On the $14,400 recapture in the earlier example, a taxpayer in the 24% bracket owes roughly $3,456 in additional tax plus about $691 in penalties, with interest running from the original due date. The penalty can reach 40% in cases involving gross valuation misstatements.

The more common risk is that the IRS finds the recapture issue while looking at something else — a vehicle deduction, a home office claim — and the adjustments compound. Reporting the recapture in the year it happens is far cheaper than being found later.

Records to Keep, and for How Long

The IRS generally has three years from the filing date to assess additional tax, but that extends to six years if unreported income exceeds 25% of the gross income shown on the return.⁹ Combined with a five- or seven-year recovery period, this means keeping Section 179 records for a decade or more from the placed-in-service date.

For every Section 179 asset, retain the purchase invoice, the original Form 4562, and documentation of business use for each year of the recovery period. For vehicles, that means the mileage log. For other equipment, keep records of where the property lives and how it is used. A laptop that migrates from the office to a teenager’s bedroom does not generate its own paper trail, and documenting the shift before it becomes a dispute is the only real defense.⁴

State Rules Can Change the Number

Not every state follows federal Section 179 limits. Several, including California, decouple from the federal deduction, capping it at a lower amount or disallowing it entirely. If your state limited or disallowed the original deduction, the state recapture will not match the federal figure, and in some cases there is no state recapture at all because the state never allowed the deduction. Check your state’s conformity rules before assuming the federal number carries over.

1
Office of the Law Revision Counsel. 26 USC 179 – Election to Expense Certain Depreciable Business Assets
2
Office of the Law Revision Counsel. 26 USC 168 – Accelerated Cost Recovery System
3
Internal Revenue Service. Publication 946 (2025), How To Depreciate Property
4
Internal Revenue Service. Publication 463 (2025), Travel, Gift, and Car Expenses
5
Internal Revenue Service. About Form 4797, Sales of Business Property
6
Internal Revenue Service. Instructions for Form 4797 – Sales of Business Property
7
Internal Revenue Service. 2025 Shareholder’s Instructions for Schedule K-1 (Form 1120-S)
8
Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments
9
Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection