How soon before my fix ends should I remortgage?

Start shopping about 6 months before your fixed rate ends. UK mortgage offers typically last 6 months, so you can lock in a new deal now and arrange completion on the exact day your Early Repayment Charge expires — avoiding even a single month on the 7.5-9.0% Standard Variable Rate. Most lenders also give you a rate-switch right if best-buys drop between application and completion, so locking early is rarely a one-way bet.

Why 6 months is the magic window

Two calendar rules govern the timing. First, almost every UK lender now issues mortgage offers valid for 6 months (some go to 9). That means you can apply for a new deal today, receive a formal offer, and sit on it until your current fix ends without re-applying. Second, your Early Repayment Charge falls off on the last day of the fix — switch one day earlier and you pay an ERC of 1-5% of the outstanding balance. Switch one day later and you’re on SVR.

Line those two rules up and the answer is simple: apply 5-6 months out, complete on the ERC-expiry day.

What does the SVR cliff look like?

This is where procrastination gets expensive. Most UK Standard Variable Rates sit at 7.5-9.0% in April 2026, against a best-buy 5-year fix near 5.75%. On a £200,000 balance that’s a difference of around £250-£370 a month. A single month on SVR erases most of your first year’s savings from switching.

Remaining balance	SVR @ 8.0%	Best-buy 5-yr fix @ 5.75%	Monthly gap
£100,000	£772	£629	£143
£200,000	£1,544	£1,258	£286
£300,000	£2,316	£1,886	£430

For a £300,000 remortgage, each month you leave it costs you more than the typical £999 product fee. That’s the whole case for starting early.

A homeowner ticking a remortgage task list with a laptop open to a comparison site — Six months is the right lead time: long enough to apply and be offered, short enough that rates won’t shift meaningfully against you.

Do I have to commit now if rates might fall?

No — and this is what trips up cautious remortgagers. Almost every major UK lender now operates a rate-switch or “better rate” policy on new applications. Once your mortgage offer is issued, if that same lender’s rates drop before completion, you can usually ask to switch onto the cheaper deal at no charge. Barclays, Nationwide, Santander, Halifax, NatWest and HSBC all offer some form of this, though the cut-off tends to be 7-14 days before completion.

In practice that means locking in a deal 5-6 months out acts as insurance — you’ve capped your rate at today’s level, but kept the upside if the Bank of England cuts Bank Rate (currently 3.75%) and pricing softens. Use our remortgage calculator to see how much a 0.2pp drop in the fix would save you.

What’s the month-by-month timeline?

For a fix ending on, say, 30 September 2026:

April (6 months out) — Start shopping. Use a whole-of-market broker or compare direct. Request a product-transfer quote from your existing lender too.
May-June (4-5 months out) — Submit the application. Full underwrite, valuation and offer usually takes 2-4 weeks.
June-July (3-4 months out) — Mortgage offer issued. Relax — you are now rate-capped.
September (1 month out) — Conveyancing completes the charge transfer.
30 September — New deal starts. Old fix ends. Zero days on SVR.

For a pure product transfer with your existing lender, the window is shorter because there’s no solicitor involved — 3-4 months is fine.

Is it ever too early?

A little. Before 6 months out, most lenders will not yet offer you a new deal because your current one is still active and the offer validity wouldn’t stretch to the switch date. Pencil in the date 6 months before expiry and trigger the process then. If you’re within 3 months and haven’t started, move today — see our what happens if I don’t remortgage guide for how to limit the SVR damage.

The misconception worth clearing up

“Best rates always come out closer to my switch date” — there’s no law that says so. Mortgage pricing tracks swap rates and lender appetite, not your calendar. In 2024-2025, homeowners who waited “just in case something better appears” ended up on SVR for a quarter and paid thousands more than if they’d locked 6 months out. Plan for the worst-case (rates rise), accept the rate-switch option as free insurance, and book in on the day you hit the 6-month line.

This is information, not regulated advice — a whole-of-market broker can walk through the exact timing for your lender.