Enter a loan balance or principal and the annual interest rate (%) to calculate the quarterly interest owed on the loan.

Quarterly Interest Calculator

Enter any 2 values to calculate the missing variable








Quarterly Interest Formula

The following formula is used by the calculator above to determine the quarterly interest of a loan or mortgage.

QI = LB X AIR / 400
  • Where QI is the quarterly interest ($)
  • LB is the loan balance ($)
  • AIR is the annual interest rate (%)
  • 4 represents the number of quarters in a year

To calculate quarterly interest, multiply the loan balance by the annual interest rate, convert the rate to a decimal by dividing by 100, and then divide by 4 (effectively dividing by 400).

This formula calculates the total interest you would pay each quarter on a loan throughout its lifetime. Note that actual payment schedules may vary as most loans are repaid on a monthly basis.

Quarterly Interest Definition

Quarterly interest is the interest accrued over a three-month period on a loan or mortgage, based on the annual interest rate and the loan balance.