A rate "lock" or "commitment" is a lender's promise to freeze a particular interest rate and a particular number of points for you for a specified period of time while your application is processed. This keeps you from getting through your entire application process and learning at the end that your interest rate has risen higher.
Rate lock periods can be various lengths of time, between 15 to 60 days, with the longer ones usually costing more. You can get a longer period for your lock, but in doing so, will likely have a higher rate than you would with a shorter rate lock span of time
There are other ways to get a better rate, besides choosing a shorter rate lock period. The larger down payment you pay, the smaller the rate will be, because you will be starting with more equity. You could opt to pay points to reduce your rate for the loan term, meaning you pay more initially. One strategy that makes financial sense for many people is to pay points to bring the rate down over the life of the loan. You are paying more initially, but you will save money, especially if you keep the loan for the full term.
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