Section 179 and bonus depreciation let small businesses deduct the cost of qualifying purchases immediately instead of over years of regular depreciation. Used together they can dramatically reduce taxable income in a profitable year — but they're different tools with different rules, and choosing the wrong one can leave deductions on the table or create problems in a loss year.
Section 179 vs. Bonus Depreciation
| Feature | Section 179 | Bonus Depreciation |
|---|---|---|
| 2025 limit | $1,250,000 (indexed) | 100% of cost (OBBBA) |
| Spending cap | Phase-out at $3.13M | No cap |
| Can create a loss? | No — limited to income | Yes |
| Election | Per asset | Automatic (can elect out) |
| New or used | Both | Both |
The most important practical difference is the income limitation. Section 179 cannot exceed your business's taxable income — it cannot create a loss. Bonus depreciation has no such limit and can drive income negative, creating a net operating loss that carries forward. That single distinction drives most planning decisions.
OBBBA restored 100% bonus
The One Big Beautiful Bill Act restored 100% bonus depreciation for qualifying property, reversing the scheduled phase-down. For property placed in service under the new rules, the full cost can be written off in year one through bonus alone.
When to Use Each
Section 179 is the scalpel — elected per asset and per dollar, it lets you deduct exactly as much as you want, ideal for managing income to a target bracket or preserving a QBI deduction. It also covers qualified improvements (roofs, HVAC, fire and security systems). Bonus depreciation is the sledgehammer — automatic, no spending cap, and able to create a loss for a carryforward.
Order of operations
When both apply, the standard sequence is: Section 179 first (on the assets you choose), then bonus depreciation on the remaining basis, then regular MACRS on anything left.
Heavy Vehicles
- Passenger vehicles (under 6,000 lbs GVWR): subject to annual luxury-auto caps
- Heavy SUVs/trucks (6,000–14,000 lbs): Section 179 limited (~$31,300 for 2025), but bonus can apply to the remaining basis
- Vehicles over 14,000 lbs: not subject to the caps and can often be fully expensed
- Business-use percentage governs all of it — dropping below 50% can trigger recapture
Key takeaway
Section 179 is a scalpel — deduct exactly what you want, but it can't create a loss. Bonus is a sledgehammer — full expensing, even into a loss. The best plans use both: 179 to fine-tune income to a target, bonus to capture the rest. The wrong move is reflexively expensing everything in a year when spreading deductions preserves a lower bracket or a QBI deduction.
SMAART Tax Team
CPAs & Enrolled Agents, SMAART Tax
