The only way to tell if you have negative equity is to do some math.

Your payoff (which you can get from your lender).

- minus -

The value of your vehcile (use an estimate from www.kbb.com or www.edmunds.com)

If you owe more than the vehicle is worth - you have negative equity. Sometimes it’s referred to as a “deficiency balance” or in car slang - you are “buried” or “upside down.”  All terms refer to the same thing - you are trading before you’ve paid down enough principal on your loan and will owe that extra money in order to satisfy the loan.