A rate lock gives you protection from financial market fluctuations that could affect your interest rate range. You can choose to lock or not lock your interest rate range. On the date and time you lock, that interest rate range remains available to you for a set period of time. If there are no subsequent changes to your loan and your interest rate range is locked, the interest rate range on your application generally remains the same. If there are changes to your loan, your final interest rate at closing may be different.