If you used the standard mileage rate for the business use of your car, depreciation was included in the standard mileage rate.
- You'll have to pull all your tax returns and using the IRS Depreciation Adjustment for Standard Mileage Rate (screenshot below), calculate the amount by which you have to reduce your cost basis.
Since depreciation accumulates, each year's business mileage affects the adjusted basis of the vehicle. The adjusted basis will, in turn, be used to determine the gain or loss when the vehicle is sold or disposed of, so keeping good records is essential.
- The 2018 portion of the business standard mileage rate that is treated as depreciation is 25 cents per mile. For tax years 2017 and prior, see the screenshot below.
-
Note: my screenshot also has an example that shows how to do the calculation.
See Business Use of Vehicles https://turbotax.intuit.com/tax-tools/tax-tips/Small-Business-Taxes/Business-Use-of-Vehicles/INF1207...
