How This Calculator Works
1. The category: property class and recovery period
Every asset has an IRS class life (Publication 946, Appendix B) that sets its GDS recovery period (3, 5, 7, 15 years…) and a longer ADS recovery period. What counts is what the asset is, not how much it is driven or used. A food truck that stays parked in one spot is still a truck: 5-year property. Its built-in kitchen equipment would be 5-year property anyway (class 57.0). Depreciation starts when the asset is ready and available for its job and continues even while it sits idle.
2. The order of the deductions
First Section 179 (you choose the amount, up to $2,500,000 for 2025 and $2,560,000 for 2026; heavy SUVs are capped at $31,300 for 2025 and $32,000 for 2026; and it can't exceed your business income). Then bonus depreciation on what is left: 100% for property acquired after January 19, 2025, or 40% (2025) / 20% (2026) for property acquired earlier. Then regular MACRS on the remainder. Section 179 needs more than 50% business use and isn't available for property you used personally before.
3. MACRS
Regular MACRS (200% declining balance for 3- to 10-year property, 150% for 15- and 20-year property) uses the IRS percentage tables from Publication 946, Appendix A (Tables A-1 to A-5). The other methods (the 150% election, straight line, ADS) use the Publication 946 formulas, with the rates rounded the same way as the tables. The half-year convention applies, or mid-quarter when more than 40% of the year's purchases were placed in service in October–December. Each year is rounded to whole dollars, and the last year takes what is left. Checked against the worked examples in Publications 946 and 463 and Rev. Proc. 2019-13.
4. Cars and other passenger automobiles (6,000 lb or less)
Total depreciation, including bonus and Section 179, is capped each year: for 2025, $20,200 in year 1 with bonus ($12,200 without), $19,600 in year 2, $11,800 in year 3 and $7,060 a year after that; for 2026, $20,300 ($12,300), $19,800, $11,900 and $7,160. The caps are multiplied by the business-use percentage. With 100% bonus, years 2–6 follow the IRS safe harbor in Rev. Proc. 2019-13; any cost left after the recovery period is deducted at the later-year cap until it is used up. A truck or van that has been specially modified so it is unlikely to be used personally (a food truck, a van with permanent shelving and the business name painted on) is a qualified nonpersonal use vehicle: no caps.
5. Income and losses
If you enter your profit, Section 179 is limited to business taxable income (for individuals, wages count too), and the unused part carries forward to the next year. Bonus and MACRS can create a loss. For a sole proprietor, a loss first offsets other income on the same return; what is left becomes a net operating loss that can only be carried forward, offsets at most 80% of taxable income in a later year, and does not reduce self-employment tax.
6. Not covered
Selling the asset (depreciation recapture), several assets placed in service in the same year, trade-ins, short or fiscal tax years, changes in business use after the first year, leased vehicles, the alternative minimum tax, the excess business loss limit, qualified production property, and state depreciation rules (many states don't follow federal bonus depreciation).
Sources
- IRS Publication 946 (2025), How To Depreciate Property: Section 179 limits for 2025 and 2026, bonus depreciation, MACRS, listed property, Appendix B asset classes
- IRS, Instructions for Form 4562 (2025): election out, qualified nonpersonal use vehicles, conventions, passenger automobile limits
- IRS Notice 2026-11: 100% bonus depreciation under Public Law 119-21, the 40% election and the election out
- Rev. Proc. 2026-15 (Internal Revenue Bulletin 2026-13): 2026 passenger automobile limits; 20% bonus for property acquired before January 20, 2025 and placed in service in 2026
- Rev. Proc. 2025-16: 2025 passenger automobile limits
- Rev. Proc. 2019-13: safe harbor for passenger automobiles with 100% bonus depreciation
- Rev. Proc. 2025-32, section 4.24: 2026 Section 179 limits
- IRS, Additional First Year Depreciation Deduction (Bonus) FAQ: used property, related parties, carryover basis
- IRS Publication 463, Travel, Gift, and Car Expenses: accountable plans, standard mileage rate
- IRS, Instructions for Form 172: net operating losses, the 80% limit
- IRS, Instructions for Schedule SE: net operating losses don't reduce self-employment income
Want the plain-English version? Read our guide: Can I Write Off My Business Vehicle or Equipment This Year?