Gap Insurance Calculator

No -- the underwater amount only compares your loan balance against the vehicle's estimated market value, and your deductible never enters that comparison. Your deductible only affects how much a claim would actually pay out, which in turn affects the separate gap coverage figure, not the underwater amount itself.

A higher deductible is subtracted from the estimated payout before insurance would reimburse you, so a larger deductible means a smaller expected payout on a total-loss claim -- and since the gap amount is the shortfall between your loan balance and that expected payout, a smaller payout widens the gap you would be left covering out of pocket.

Market value here compounds downward by your chosen annual depreciation rate for every year of the vehicle's age, similar to compound interest running in reverse, so a higher depreciation rate produces a lower estimated value at any given age, and the effect compounds faster the older the vehicle gets.

No -- it is a simplified estimate that assumes a rough, fixed pace of loan paydown rather than pulling from your actual amortization schedule, so it is useful as a general sense of timing but should not be treated as the precise date your specific loan balance will fall below your vehicle's value.

You only show as underwater once your loan balance exceeds the vehicle's estimated current market value -- below that crossing point the underwater amount stays at zero, since you owe less than the car could be sold or insured for, and only balances above that specific point produce a positive underwater figure.