Different lenders and loan servicers use different strategies to determine your loan to value ratio (LTV). Some calculate LTV based on your home’s original purchase price; others rely on your original home appraisal. You could also pay for a new appraisal if your home’s current value has risen since you first purchased it. An appraisal may cost as much as $500 but the fee would be worth it if your home’s current value shows you have 20 percent home equity — enough equity to cancel PMI on a conventional mortgage which will save money each month.