When you obtain a loan to purchase a home, you’re required to prepay any interest that will accrue from the date of closing until the end of the month. So, in theory, the closer your closing is to the end of the month, the less you have to pay in closing costs.
This portion of interest is charged to the buyer at closing because mortgage payments are made in arrears. Unlike paying a rent, a monthly mortgage payment actually covers the previous month. For example, if you were to purchase a home and close in January, your first mortgage payment would not be due until March 1. The payment on March 1 would cover the principal and interest owed to the lender for the month of February. For a visual illustration, take a look at the sketch above.
Regarding the prepaid interest, assume your actual closing date is January 15th. Your prepaid interest charge is as follows:
Mortgage amount: $175,000
Annual (fixed) interest rate: 6%
Daily interest charge: $28.68
Now compare the potential savings in prepaid interest when closing on the 31st vs. 15th.