When to remortgage: start six months before your fix ends

The short answer: start about six months before your fix ends, and aim for the new deal to begin the day after the old one ends. Many lenders let you secure a deal ahead of time, so you can avoid both an early repayment charge (ERC) and time on the standard variable rate (SVR). Switching earlier than that only pays if the saving beats the ERC and fees.

Whether to switch is a cost question: fees and ERCs often decide it before the rate gap does. When to start is a calendar question, and the six-month timeline below answers it. The labelled EXAMPLE later on shows what doing nothing can cost. It is illustrative only, so use your own offer and redemption statement. The last eight weeks are covered on fixed rate ending. What the SVR costs if nothing changes is on rolling onto the SVR.

Start with fees and the ERC

Before hunting rates, open your mortgage offer or ESIS and find:

• the deal end date
• whether an ERC still applies, how it is calculated, and when it falls away
• any exit or admin fees on redemption
• your outstanding balance and remaining term

Those figures set the floor for any comparison. A lower rate that needs a large ERC and several hundred pounds in legal and product fees can lose to staying put for a few more months — or to a product transfer with lower switching costs.

MoneyHelper’s remortgage guidance stresses checking costs and comparing your current lender’s retention options with other products before you switch. The Financial Conduct Authority (FCA) also notes that many borrowers can arrange a new deal so it starts when the existing one ends, which helps limit time on a reversion rate.

Our Early repayment charge estimator helps you turn a percentage ERC into a sterling figure. Our Remortgage true cost calculator folds fees, cashback and rate differences into one horizon. Neither tool is advice. Both exist so you can see the arithmetic before you speak to a lender or an adviser.

A six-month timeline before the fix ends

Treat the end date like a project deadline. Exact windows vary by lender, but a six-month runway is a workable planning frame for many households. Each checkpoint below has one job and one tool. The EXAMPLE notes use the shared site house (£185,000 · 22 years · 4.19% with 4 months left) and are illustrative only, not advice.

Six months out: find the ERC end date and the fee schedule

• Confirm the exact deal end date in writing. The original offer, the ESIS or your annual mortgage statement usually shows it.
• Note how the ERC is worked out, what it is today and the date it reaches zero. A stepped schedule changes each year, so read the row for the year you are in.
• Note any exit or admin fee on redemption and the reversion rate after the deal.
• List must-haves: overpayment limits, portability, offset, or a preference to stay with the same lender.

Tool: the ERC estimator, then when an ERC bites. EXAMPLE: 2% of £185,000 is £3,700 while the charge applies. At this stage you are collecting facts, not choosing a product.

Four to five months out: estimate LTV and check your credit file

• Estimate the property value roughly for loan-to-value (LTV) banding. A formal valuation comes later if you remortgage, and it can come in lower than you expect.
• Check your credit file with the main agencies and correct errors now, while there is time for a fix to show.
• Gather proof of income and outgoings if you expect a full affordability check with a new lender.

Tools: the LTV and equity calculator, LTV bands explained and credit and affordability when switching. EXAMPLE: £185,000 on an EXAMPLE £250,000 value is 74% LTV, just inside a typical 75% band. A valuation below about £246,667 would push it to 75% or more.

About four months out: compare a product transfer with a new lender on true cost

• Ask your current lender for product-transfer (retention) quotes and fee schedules.
• Get Agreement in Principle / Decision in Principle figures from one or more other lenders, or through an FCA-authorised broker, if you want a remortgage path on the table.
• Put both paths through a true-cost comparison over the same horizon (for example two years), including fees, cashback and any remaining ERC.
• Check whether application or broker fees are refundable if you cancel before completion. Policies differ.

Tools: the remortgage vs product transfer calculator and the comparison page. EXAMPLE, timed to the deal end so no ERC applies: over 24 months, a transfer at 4.39% with no fee costs about £15,810 in interest. A new lender at 4.14% costs about £14,897 in interest plus £1,249 net fees, so about £16,146. The transfer is ahead by about £336. The EXAMPLE house, with 4 months left, is at this checkpoint now.

Three months out: apply or reserve

• Narrow options and prefer written figures over verbal quotes. Mortgage offers are typically valid for around three to six months, and many lenders let you reserve a product transfer a few months before the deal ends, so applying now does not usually mean paying an ERC.
• Ask for completion, or the new product start date, to be set for the day the ERC falls away, not the day the offer is issued.
• Ask whether you can move to a cheaper product before completion if rates fall.

Read: remortgage documents checklist and how to read an illustration.

Six to eight weeks out: legal work, valuation and the switch date

• If remortgaging, chase the valuation and the conveyancer. Legal work is the step that most often slips.
• If staying, check the transfer has been accepted and that the new rate starts the day after the old one ends.
• Re-read the new offer for fees added to the loan, cashback conditions and the new ERC schedule.

Read: how long a remortgage takes.

Final two weeks: match completion to the fix end

Confirm in writing that completion, or the transfer start date, falls on or just after the fix end. Too early and the ERC can still apply. In the EXAMPLE that would be the full £3,700. Too late and you pay the reversion rate in the gap. If a slip is unavoidable, see rolling onto SVR.

The final weeks are a different page

The last two checkpoints are deliberately short. Once you are inside the last eight weeks, the documents to have open and what to do week by week are on fixed rate ending. The point of starting at six months is so that page is a confirmation, not a rescue.

EXAMPLE: what SVR can cost if you do nothing

Here is our site EXAMPLE house. Rates that are not live market prices are labelled EXAMPLE.

• Outstanding balance: £185,000
• Remaining term: 22 years
• Current fixed rate: 4.19%
• Months left on the fix: 4
• EXAMPLE ERC if you left early at 2% of balance: £3,700
• EXAMPLE SVR after the fix: 7.49%

7.49% is an EXAMPLE SVR, not a live or lender rate; use the reversion rate in your own offer.

On a capital-and-interest repayment basis, with the balance and term above held constant for a simple comparison:

• Monthly repayment at 4.19%: about £1,074
• Monthly repayment at the EXAMPLE 7.49% SVR: about £1,432
• Monthly difference: about £358
• Extra cost over 12 months on EXAMPLE SVR vs the current fix: about £4,294

Those figures ignore further capital repayment reducing the balance, and they ignore any later change in the SVR. They show why drifting onto a high reversion rate can matter once the fix ends. Four months of the current fix still remain in this EXAMPLE, so the immediate work is usually preparation — not paying the EXAMPLE ERC to leave today.

If you instead left early to chase a new rate, the EXAMPLE £3,700 ERC would need to be earned back through lower payments after fees. That is what the true cost and ERC tools are for.

Product transfer versus remortgage timing

On timing alone, a product transfer with your current lender can often be booked months ahead and switched on the end date with little legal work. A move to a new lender needs a valuation, conveyancing and full underwriting, so it needs the earlier start in the timeline above. How each path works is covered inproduct transfer explained, so this page sticks to the calendar.

Neither path is universally better. The calendar, the ERC window, fee stacks and eligibility decide.

Checklist before you compare rates

• ERC end date and calculation method from your offer
• Current balance, remaining term, and a realistic property value for LTV
• Product, valuation, legal and broker fees on any new deal, plus cashback
• Whether fees are paid upfront or added to the loan
• Features you need: overpayments, portability, offset
• Whether a product transfer quote exists alongside remortgage quotes
• Time needed for valuation and conveyancing if switching lender

Sources, checked 2 November 2026: MoneyHelper on remortgaging (deals usually last two to five years before moving to the SVR, and it suggests looking around six months before the deal ends) and the FCA consumer mortgages page (offers usually valid for three to six months; reversion is often to the SVR).

Illustrative only: not personalised advice, not a mortgage offer and not an FCA-regulated recommendation. Your offer and ESIS set the real ERC, fees and terms; the ERC estimator and true cost calculator take your own figures.