Fixed-Rate vs. Adjustable-Rate Loans

How fixed and adjustable rates differ, and the risks and benefits of each.

When you borrow, you will often be offered a fixed rate or an adjustable rate. The choice affects how predictable your payment is, how much risk you carry and how much you may pay over time.

Fixed-rate loans

A fixed rate stays the same for the whole term. Your principal and interest payment never changes, which makes budgeting simple. Most auto loans, personal loans and many mortgages are fixed. The trade-off is that fixed rates may start higher than the initial rate on an adjustable loan, and you cannot benefit automatically if market rates fall unless you refinance.

Adjustable-rate loans

An adjustable-rate loan, often called an ARM when applied to a mortgage, usually has a fixed rate for an initial period, then changes at set intervals. The new rate is typically based on a benchmark index plus a margin set by the lender. Your payment can rise or fall at each adjustment.

Reading ARM terms

A "5/1 ARM," for example, has a fixed rate for 5 years and adjusts once a year after that. Look for rate caps, which limit how much the rate can change at each adjustment and over the life of the loan. Ask what index is used and what the maximum possible payment could be.

An illustrative comparison

Suppose you borrow $300,000 over 30 years. At a fixed 6.5%, the payment is $1,896.20. If an ARM started at 5.5% the payment would be $1,703.37, saving about $193 a month at first. If the rate later adjusted to 8.5% on the remaining balance, the payment would be higher than the fixed loan. These rates are examples, not forecasts.

When a fixed rate fits

• You plan to keep the loan for many years.
• Your budget is tight and surprises would be hard to absorb.
• You prefer certainty over a possible saving.

When an adjustable rate might fit

• You expect to sell or refinance before the fixed period ends.
• Your income is likely to grow substantially.
• You can afford a higher payment if the rate rises to its cap.

The risk of "payment shock"

Payment shock occurs when an adjustment raises your payment sharply. Borrowers who counted on refinancing sometimes find that rates or their finances have changed, leaving them stuck. Before choosing an ARM, calculate the payment at the maximum rate and decide whether you could handle it.

Other adjustable products

Credit cards, home equity lines of credit and some student and private loans have variable rates that move with an index. The same questions apply: what index, what margin, and what limits exist on changes.

Questions to ask a lender

• How long is the fixed period, and how often does the rate adjust?
• What are the periodic and lifetime caps?
• What is the worst-case payment?
• Are there prepayment penalties if I refinance?

Test scenarios

Try the loan calculator or the mortgage calculator with different rates to see how payments change if your rate moves up or down.

Reading the disclosure

Lenders must provide written disclosures for adjustable-rate loans that explain the index, margin, caps and an example of how payments could change. Read them closely and ask the lender to walk through the worst-case numbers before you sign. If any term is unclear, request a written explanation, and consider asking a HUD-approved housing counselor for an independent view.

Key takeaway

Choose the loan whose payment you could still afford in the worst case, not just the one with the lowest starting rate.

Important

This guide is educational and not individualized financial advice. Loan terms vary by borrower, lender and market, so confirm details in the official disclosure.