Annual percentage charged on the unpaid mortgage principal, excluding most fees and other housing costs.
A mortgage interest rate is the annual percentage charged on the unpaid principal balance for borrowing the mortgage money.
The interest rate directly affects the principal-and-interest portion of the monthly payment and the amount of interest that accrues over time. Because mortgage balances are large and repayment periods are long, a difference of a fraction of a percentage point can materially change affordability.
The rate does not include property taxes, homeowners insurance, mortgage insurance, association dues, or most closing fees. Those amounts can still change the total monthly housing payment and cash needed at closing.
Borrowers also need to distinguish a market-rate headline from a transaction-specific rate. The rate available to one borrower depends on the loan program, term, property, occupancy, down payment, credit profile, points or credits, and lock period.
Interest-rate language appears throughout the mortgage:
For a fixed-rate mortgage, the note rate remains fixed for the loan term. For an adjustable-rate mortgage, the initial rate applies for a defined period and later changes under the index, margin, cap, and adjustment rules in the note.
| Feature | Fixed-rate mortgage | Adjustable-rate mortgage |
|---|---|---|
| Initial rate | Set at closing | Set for the introductory period |
| Later changes | Does not change under the note | Can reset on scheduled adjustment dates |
| Payment risk | Principal and interest is predictable | Principal and interest can rise or fall |
| Key document terms | Note rate and loan term | Initial rate, index, margin, caps, and adjustment period |
An ARM’s starting rate may be below its Fully Indexed Rate. Borrowers should not treat the introductory payment as the maximum future payment.
| Pricing factor | Borrower-facing effect |
|---|---|
| Market conditions | Available rate-and-point combinations can change before locking |
| Loan term and product | A 15-year fixed loan can price differently from a 30-year fixed or ARM |
| Credit and leverage | Risk-based adjustments can alter the cost of obtaining a rate |
| Occupancy and property | Primary residence, second home, investment, condo, and unit count can price differently |
| Discount Points | More upfront cost may buy a lower rate |
| Lender Credits | A higher rate may produce credit toward closing costs |
| Lock Period | Longer protection can carry worse pricing than a shorter lock |
These factors affect the offered transaction price. They do not mean interest starts accruing on fees or taxes as if those amounts were part of principal unless they are actually financed into the loan.
Consider a $350,000, 30-year fixed-rate mortgage:
| Rate | Approximate monthly principal and interest |
|---|---|
| 6.250% | $2,155.17 |
| 6.500% | $2,212.24 |
| Difference | $57.07 |
Over 60 payments, the gross payment difference is about $3,424.20 before accounting for the different principal balances remaining under the two amortization schedules. The comparison demonstrates scale; a complete cost analysis also includes points, credits, fees, and expected payoff timing.
The comparison assumes the same loan amount and term and excludes taxes, insurance, mortgage insurance, and association dues. It also does not show whether one rate requires more points. The borrower should compare the full Loan Estimate, not the payment alone.
Mortgage interest rate differs from Interest. Interest is the dollar cost that accrues; the rate is the percentage used to calculate that cost.
It differs from Note Rate. Interest rate can describe a quoted or general rate, while note rate specifically means the contractual rate stated in the signed note.
It differs from APR. APR is a standardized annualized cost measure that incorporates the interest rate and certain finance charges. It is usually higher than the note rate on a typical fixed-rate mortgage with borrower-paid finance charges.
It differs from Par Rate. Par rate is a pricing reference associated with no discount points and no rate-based lender credits at a particular time; the borrower can choose a different note rate and cost combination.