Fixed vs variable rate mortgages: what's the difference?

One of the first choices you'll bump into when you look at a mortgage is whether the interest rate is "fixed" or "variable". It sounds technical, but the idea underneath is simple — so let me walk you through both, in plain English, with no thumb on the scale either way.

The one-line version

The interest rate is what your lender charges you for borrowing the money. A fixed rate stays the same for an agreed period, so your interest rate — and usually your monthly payment — doesn't move during that time. A variable rate can go up or down while you're on it, which means your payments can change too.

That's really the whole distinction: fixed means certainty for a set window; variable means your rate moves with something outside your front door. Everything else is detail — and I'll unpack the detail below so you can see what each one actually feels like to live with.

How a fixed rate works

With a fixed rate, you agree a rate for a set length of time — commonly two, three or five years, and sometimes longer. During that period your interest rate is locked, so if rates rise across the market, yours doesn't; and if they fall, yours doesn't drop either. When the fixed period ends, you're usually moved onto the lender's variable rate unless you arrange a new deal (a lot of people look at remortgaging around that point).

• What people tend to like: predictable payments make budgeting easier, because you know what's leaving your account each month for the fixed term.
• The trade-off: if market rates fall, you don't benefit until your deal ends. Fixed deals also often come with early repayment charges — a fee if you leave or overpay beyond a set limit before the period is up.

A fixed rate suits some people's circumstances well and others less so — that depends entirely on your situation, not on the product being "better".

How variable rates work

"Variable" is really an umbrella term covering a few different things, so it's worth knowing which is which:

• Tracker: follows an external benchmark — usually the Bank of England base rate — plus a set margin. If the base rate moves, your rate moves with it in step.
• Standard variable rate (SVR): the lender's own default rate, which they can change more or less when they choose. It's typically what you roll onto after a fixed or tracker deal ends.
• Discounted variable: a set discount off the lender's SVR for a period — so it still moves whenever the SVR does.

• What people tend to like: if rates fall, your payments can fall too, and some variable deals have no early repayment charges, giving more flexibility to overpay or move.
• The trade-off: your payments can also rise, sometimes at short notice, so you need room in your budget to absorb that.

Things worth weighing up on both

Whichever way you lean, a few practical things shape the real cost and how it fits your life:

• Early repayment charges: common on fixed deals and some variables. They matter if there's any chance you'll move home, repay early, or want to overpay a lot.
• Product or arrangement fees: some deals carry an upfront fee and some don't. A lower headline rate with a big fee isn't automatically cheaper overall — it depends on your loan size and how long you keep the deal.
• How long you want certainty for: a longer fix buys more years of stable payments but usually less flexibility; a shorter deal or a variable gives more flexibility but less predictability.
• Your own headroom: how comfortable your budget is if payments were to rise is a personal question — only you (and your adviser) can answer it honestly.

None of these point to a single right answer. They're the levers a good adviser will actually talk through with you.

So which is "better"?

Here's the honest bit: neither is better in the abstract. Fixed and variable are just two ways of pricing the same loan, each with a different balance of certainty and flexibility. The "right" one is entirely about your circumstances — how steady your income is, how you'd cope if payments changed, how long you plan to stay, and how much you value knowing the number in advance.

That's also why comparing deals on the headline rate alone can be misleading. The fees, the charges for leaving, the length of the deal and what happens when it ends all feed into the real picture. It's a lot to hold in your head at once, which is exactly where a qualified human adviser earns their keep — they weigh it all against your situation and search the whole market for you.

Your home may be repossessed if you do not keep up repayments on a mortgage or any other debt secured against it. This guide is general information, not advice.