I have a vehicle that was disposed of (traded in) during 2019.  It was originally purchase in 2014 and converted to partial business use in 2015.  Business use was minimal (less than 5%) and only used standard mileage.   You still have to calculate whether there was a business gain/loss, correct?

If so, would you use the standard mileage depreciation table per IRS Pub 463 and calculate depreciation based on business miles to deduct from basis?  And then use average business use to calculate portion of sale/basis attributable to the business versus personal?