Calculate non-compounding simple interest on a loan — principal × rate × time — the way some short-term and add-on installment loans work.
Enter your loan details
$
%
years
Your results
$0
Total Interest
$0
Total Repayment
$0
Equal Monthly Installment
0
Loan Term in Months
Balance (straight-line decline)
How the Simple Interest Loan Calculator works
Most loans you'll encounter — mortgages, auto loans, most personal loans — use amortized
interest, recalculated every month on your remaining balance. Simple interest is different: it's
calculated just once, up front, on the full original principal for the entire loan term, with no
compounding.
Because the total interest is fixed from day one, this calculator can find it directly, then
divide the total repayment evenly across the term to get an equal monthly installment. There's no
month-by-month amortization schedule to build, since the interest doesn't depend on how much
balance remains.
Interest = Principal × Rate × Time (Time in years)
Total Repayment = Principal + Interest
The chart above shows the balance declining in a straight line from the full loan amount to zero,
since each equal installment reduces it by the same amount every month — unlike an amortized
loan, where the balance falls faster later in the term as more of each payment shifts to
principal.
Frequently asked questions
Simple interest is calculated once, up front, on the original principal for the full loan term, and doesn't change based on your remaining balance. Amortized interest is recalculated every month on whatever balance is left, so it shrinks as you pay the loan down. See the Loan Interest Calculator, or the comparison on our home page, for how amortized interest works.
Simple interest is common on some short-term loans, certain add-on installment loans, and some payday or title loans. Most mortgages, auto loans, and personal loans from banks and credit unions use amortized interest instead.
It depends on the loan. Because simple interest is often calculated once for the full term rather than recalculated monthly on your remaining balance, paying early may not reduce the interest already built into your schedule the way it would on an amortized loan. Check your loan agreement to see how your lender actually applies early payments.