When you are promised a "rate lock" from your lender, it means that you are guaranteed to get a certain interest rate over a determined period while you work on your application process. This prevents you from working through your entire application process and discovering at the end that your interest rate has gotten higher.
Rate lock periods can be various lengths of time, between fifteen to sixty days, with the longer ones generally costing more. You can get a longer period for your lock, but in doing so, will probably have a higher interest rate than you would with a shorter period
There are more ways to get a reduced rate, besides agreeing to a shorter rate lock period. The bigger the down payment, the lower your rate will be, as you will have more equity from the beginning. You may choose to pay points to improve your rate for the loan term, meaning you pay more up front. One strategy that is a good option for some is to pay points to reduce the rate over the term of the loan. You'll pay more initially, but you will save money in the end.
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