A lock-in, or rate lock, is a commitment from a lender to hold a certain interest rate for a certain amount of time. This allows the borrower to lock-in at a particular interest rate while their home loan application is processed.

Many home lenders offer 30-60 day rate locks, giving the borrower time to process the loan without being subject to daily fluctuations in interest rates. Lock-ins may also offer a “float-down” option where the borrower can float down to a lower interest rate if the rates move lower.

Rate locks may be offered at no cost, but extending a rate lock or asking for an excessively long timeframe may involve additional fees paid to the lender.