When you are offered a "rate lock" from your lender, it means that you are guaranteed to get a specific interest rate for a determined period while you work on the application process. This ensures that your interest rate won't grow during the application process.
Rate lock periods can vary in length, between 15 to 60 days, with the longer spans generally costing more. You can get a longer period for your lock, but in doing so, will most likely have a higher rate than you would have with a shorter rate lock period
In addition to opting for the shorter lock period, there are several ways you are able to get the lowest rate. The bigger down payment you pay, the smaller the interest rate will be, since you will be starting with more equity. You could opt to pay points to bring down your rate for the loan term, meaning you pay more up front. One strategy that makes financial sense for some is to pay points to improve the rate over the life of the loan. You pay more up front, but you will save money in the end.
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