What's the difference between Section 179 and bonus depreciation?

Section 179 is elected per asset, limited to a dollar cap and to your business income (it cannot create a loss). Bonus depreciation applies automatically to qualifying property, has no spending cap, and can create or increase a loss. Most plans use both.

Can I write off a vehicle with Section 179?

Yes, but the deduction depends on the vehicle's weight and business-use percentage. Passenger vehicles face annual luxury-auto caps; heavy SUVs (6,000–14,000 lbs) have a specific 179 cap but can then use bonus; vehicles over 14,000 lbs can often be fully expensed. Business use must exceed 50%.

Should I always take the maximum deduction?

No. In a low-income year, spreading depreciation into future higher-income years can be worth more. Near a bracket or QBI threshold, deducting exactly enough — not everything — can preserve a larger benefit.

What happens if business use of an asset drops below 50%?

If business use of Section 179 property (including vehicles) falls to 50% or below before the end of its recovery period, you must recapture the excess deduction — the difference between what you expensed and what regular depreciation would have allowed — as ordinary income. Tracking business-use percentage each year is essential to avoid an unexpected recapture bill.

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Business & Corporate Tax

Section 179 and Bonus Depreciation: Accelerating Deductions on Purchases

Section 179 and bonus depreciation let businesses deduct qualifying purchases immediately instead of over years. Used together they can dramatically cut taxable income — but they're different tools, and the wrong choice leaves money on the table.

SMAART Tax Team

March 27, 2026

4 min read

|Reviewed by Lisa Terrell, Enrolled Agent