A High-Ratio mortgage is one with an amount greater than 80% of the value of the property being purchased. Value is determined by the lesser of purchase price or appraised value. High-Ratio mortgages require Mortgage Loan Insurance.
A conventional mortgage is one where the down payment is equal to 20% or greater of the purchase price, or a loan to value (LTV) of 80% or less. Conventional mortgages do not normally require Mortgage Loan Insurance.