If you’re shopping for a home loan, you’ve likely heard the term “buying down your rate.” But is it really worth it? Let’s do the math together. Say you lock in a 6.5% interest rate  — your monthly principal and interest would be around $3,160 . Now, if you decide to buy down the rate  to 6.25% , it’ll cost you roughly $6,200 upfront . Your new monthly payment would be $3,079 , saving you just $81 per month .