LVR is used by lenders to determine how much they will lend against a property for a particular loan product. For example, your house is worth $500,000 and the loan product you want, allows a maximum LVR of 80%. In this case, the maximum amount you can lend is $400,000 (i.e. $400,000 loan as a percentage of a $500,000 value = 80% LVR).
