A rate "lock" or "commitment" is a lender's promise to set a certain interest rate and a particular number of points for you for a certain period of time during your application process. This ensures that your interest rate won't get higher during the application process.
Although there may be a choice of rate lock periods (from 15 to 60 days), the extended spans are typically more expensive. You can get a longer period for your lock, but in doing so, will most likely have a higher rate than you would with a shorter span of time
In addition to choosing the shorter rate lock period, there are other ways you may be able to attain the lowest rate. The bigger the down payment, the lower your rate will be, because you will have more equity from the beginning. You can pay points to improve your interest rate over the term of the loan, meaning you pay more initially. One strategy that makes financial sense for some is to pay points to reduce the rate over the term of the loan. You pay more initially, but you will save money, especially if you keep the loan for the full term.
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