Fixed Interest Rate

What Is a Fixed Interest Rate?

A fixed interest rate is an interest rate that stays the same for the full term of a loan, bond, or other debt. The borrower or issuer agrees to pay a set percentage of the principal, and that percentage does not change when market rates move. Fixed rates are common on home mortgages, car loans, and many government and corporate bonds.

How It Works

On a fixed-rate loan, interest is calculated on the outstanding balance using the locked-in rate. For a standard loan repaid in equal installments, the monthly payment usually stays the same from start to finish, while the split between interest and principal shifts over time. Early payments carry more interest and later payments carry more principal, a process known as amortization.

Interest for one year can be estimated with this formula:

Annual interest = Outstanding balance × Fixed rate

For example, a $10,000 balance at a fixed 5% rate accrues about $500 of interest over a year before any principal is repaid. Because the rate does not change, the cost of borrowing is known in advance.

With a bond, the fixed rate is called the coupon rate. The issuer pays a set amount on a regular schedule until maturity. The bond's market price can still change, because newly issued bonds may pay different rates. When market rates rise, existing fixed-rate bonds generally become less attractive and their prices tend to fall. When market rates fall, their prices tend to rise.

Advantages and Disadvantages

• Predictable payments make budgeting easier.
• Borrowers are protected if market rates rise.
• If market rates fall, a borrower may keep paying a higher rate unless they refinance, which can carry fees.
• Fixed rates often start higher than introductory variable interest rate options, though this depends on market conditions.
• Bondholders who sell before maturity can face losses if prices have dropped, which is a form of interest rate risk.

Why It Matters to Investors

Fixed-rate instruments give investors a known stream of income, which can help with planning. A key point is that a fixed payment does not mean a fixed market value. Comparing a bond's coupon with current market yields shows how the investment may behave if rates change.