Fixed vs variable rate mortgage: which is right for you?

The choice between a fixed and a variable (adjustable) rate mortgage is one of the most consequential decisions in the homebuying process. There is no universally correct answer. It depends on your tolerance for risk, your finances and how long you plan to stay in the home, and where interest rates are heading. This guide gives you a clear framework to decide.

• Fixed: the same payment every month for the life of the loan
• ARM: lower initial rate, then periodic adjustments that can save or cost money depending on rates
• If you plan to stay less than 7 years, an ARM often wins on cost
• Rate caps on ARMs limit increases (typically 2% per adjustment, 5–6% lifetime)
• In a falling rate environment, ARMs benefit automatically; fixed rates require refinancing
• Compare total cost over your expected ownership period, not just the initial monthly payment

How each type works

Fixed-rate mortgage: the interest rate is set at closing and never changes for the life of the loan (typically 15 or 30 years in the US). Your monthly principal and interest payment is identical every month, from the first payment to the last. Variable-rate mortgage (an ARM, or Adjustable Rate Mortgage, in the US; a tracker mortgage in the UK): the rate is fixed for an initial period (typically 3, 5, 7, or 10 years) then adjusts periodically, usually once a year, based on a benchmark rate plus a margin. In the US, ARMs typically track the SOFR (Secured Overnight Financing Rate). In the UK, tracker mortgages follow the Bank of England base rate.

Fixed rate: advantages and disadvantages

Advantages: the payment is completely predictable, so you know what you owe every month for the life of the loan, and a rise in rates does not touch you. Simpler to budget and plan around. Ideal for risk-averse borrowers and long-term homeowners. Disadvantages: initial rate is typically higher than the starting rate on a comparable ARM. If rates fall significantly, you are stuck paying the higher rate unless you refinance (which has closing costs). Less flexibility for short-term ownership.

Variable rate: advantages and disadvantages

Advantages: a lower initial rate. A 5/1 ARM might start 0.5–1 point below a comparable 30-year fixed, saving hundreds per month in early years. If rates fall after the fixed period, your rate adjusts down automatically. Better for borrowers planning to sell or refinance within the fixed period. Disadvantages: once the fixed period ends the payment is no longer predictable and can rise sharply. Rate caps exist (typically 2% per adjustment, 5–6% lifetime) but still allow substantial increases. Requires a financial buffer to absorb payment increases.

How the rate cycle affects the choice

After the Federal Reserve raised rates aggressively from near zero to 5.25–5.5% between 2022 and 2023 to combat inflation, 30-year fixed mortgage rates hit 7–8% in the US, the highest since 2000. Rates then started to come down again. Cycles like this create a recurring dynamic: when fixed rates are coming down from peaks, variable rates may also fall as adjustments reflect lower benchmarks. When fixed rates are elevated and expected to fall, ARMs can make more sense, but only if you are confident about where rates are heading, and nobody can be sure of that.

Practical example with real numbers

$400,000 mortgage over 30 years. Fixed at 6.8%: monthly payment $2,613, total interest paid $540,680. 5/1 ARM starting at 6.0%: monthly payment $2,398 for the first five years, saving $215 a month ($12,900 over five years). After year 5, if rate adjusts to 7.5%: payment jumps to $2,726/month. If adjusted to 9% (worst case within cap): payment reaches $3,002/month. The ARM saves money in years 1–5, but the benefit depends entirely on what happens at year 5 and beyond. If you plan to sell in 5–7 years, the ARM wins almost certainly. If you are in this home for 20+ years, the fixed provides more certainty.

How to choose based on your situation

Choose fixed if: you plan to stay in the home for more than 7–10 years, your budget is tight and you cannot absorb a payment increase, you have low risk tolerance or variable income, or current fixed rates are near historical norms. Choose variable (ARM) if: you plan to sell or refinance within the fixed period (5–7 years), you have financial reserves to handle potential payment increases, you believe rates will fall during your ownership period, or the rate difference is large enough (0.75%+) to justify the risk. Neither choice is permanent: refinancing is there if rates move enough to justify it.

Frequently asked questions

What is the difference between a fixed and a variable mortgage?

A fixed rate keeps the same payment for the whole term. A variable rate changes periodically with a benchmark, such as Euribor or a Treasury index.

Which is cheaper?

Variable usually starts cheaper, but you take on the risk of rates rising. Fixed costs a premium for certainty.

What is a mixed or hybrid mortgage?

A fixed rate for an initial period followed by a variable rate for the rest of the term.

How do I decide?

If a payment increase would strain your budget, fixed gives peace of mind. If you have margin and a short horizon, variable can be cheaper.