Deductions & credits

Are you subject to AMT this year? In other words, has TurboTax asked you about AMT preference items? If not, what you enter for AMT won't affect your return. If it looks like AMT depreciation was the same as regular, then enter the same for both.

If you have the Depreciation Report from 2019,  you should be able to look up the percentage for the next year (2020) in IRS Pub 946 Appendix A. You will need the Life and Method/Convention from the report, along with the date it was placed in service. 

Find the Life and Convention table (ex: vehicles are usually 5 year 200% Half-Year, which is Table A-1), then find row for the year you need. The percentage is the intersection of the Life column and Year row. Multiply this percentage by the Adjusted Basis and the Business Use Percentage.  See an example below.

2019 Honda Accord

In Service 7/1/2019 (half-year; 2021 = 3rd year)

Business Use 66.67%

Cost Less Section 179 Less Special Depreciation = $10,000

Life 5.0 years

Method/Convention 200DB/HY

Pub 946 Table A-1, 5-year, year 3 = 19.20%

Calculation:

Adj Cost x Table A-1 x Half-Year x Bus Use = 2021 Depr Exp

$10,000 x 19.20% x 1/2 year x 66.67% Bus Use = $640