The single highest-impact remortgage decision is timing. Start too late and you'll spend months on your lender's Standard Variable Rate, paying £300-£500/month more than necessary. Break a fix too early and the ERC will likely outweigh the rate saving. This guide gives a clear decision framework: when to start, when to break early, when to hold, and how to run the break-even calculation for your specific numbers.

The default rule: start at month -6

For most UK homeowners, the right answer is:

• Start the remortgage process 4-6 months before your fix expires.
• Time the completion to the day the fix ends (or as close as practical), avoiding any time on SVR.

Lenders let you lock in a new rate up to 6 months ahead. If rates fall in the meantime, you can usually swap to a better deal. Starting at month -6 captures both upside and downside.

The 4 timing scenarios

Scenario 1: Fix ends in 0-3 months

Action: act immediately. You're in the no-ERC window — most lenders waive ERC in the last 3 months of the fix. Lock in a new rate today; complete on or near the fix end-date.

If you delay past the fix end, every month on SVR costs £200-£500 on a typical mortgage. Two months on SVR usually equals an entire year's savings from choosing the absolute cheapest product.

Scenario 2: Fix ends in 4-6 months

Action: start now. The sweet spot. Get an AIP, then a full mortgage offer. The offer is valid 6 months so it will still be valid when your fix ends. If rates fall before completion, your lender will usually let you swap to the better deal at no cost.

Scenario 3: Fix ends in 6-12 months

Action: wait, but set a reminder for month -6. Don't lock in too early — the offer expires before you can use it, forcing re-application. If you secure a rate now and it expires, you'd need to reapply and potentially face a hard credit check + valuation again.

Scenario 4: Mid-fix (1+ years remaining)

Action: do the break-even maths. See the decision framework below. Most mid-fix remortgages don't pay off, but specific circumstances (large rate drop, LTV band improvement, equity release need) can justify acting early.

Break-even framework: should I break the fix early?

The decision rule:

Break early when: Saving over remaining fix > (ERC + product fee + legal costs + value of optionality lost)

Let's work through each component for a £200,000 outstanding balance with 2 years left on a 4.99% fix and a market rate of 3.99%:

Step 1: Calculate the saving

1% rate drop on £200,000 = £2,000/year interest saved (roughly, using simple interest). Over 2 remaining years = £4,000 saving.

Strictly the saving uses amortisation maths (declining principal), but for break-even decisions the simple multiplication is close enough.

Step 2: Calculate the ERC

Year 3 of a 5-year fix typically = 3% ERC. 3% × £200,000 = £6,000 ERC.

Step 3: Add other costs

• Product fee on new mortgage: £999
• Exit fee from existing: £195
• Legal fees: £0 (free legals)
• Valuation: £0 (free)

Total cost to switch: £6,000 + £999 + £195 = £7,194

Step 4: Compare

Saving £4,000 vs cost £7,194 = net loss of £3,194. Don't break early in this scenario. Wait until the no-ERC window (last 3 months of fix).

When the maths does work

Same scenario but with a 2pp rate drop (4.99% → 2.99%) and 4 years remaining (year 1 of 5-year fix):

• Saving: 2% × £200,000 × 4 years = £16,000
• ERC: 5% × £200,000 = £10,000
• Other costs: ~£1,200
• Net saving: £4,800

Worth doing. Use the remortgage savings calculator to run your specific numbers.

Rate environment triggers

Rates have fallen since you fixed

1pp drop: Rarely worth breaking. Wait for fix end.

1.5-2pp drop with 3+ years remaining: Run the break-even. Likely worth it on year 1-2 of a 5-year fix.

2.5pp+ drop: Almost certainly worth it. Run the maths but expect to act.

Rates have risen since you fixed

Stay put. Your rate is already lower than market. Plan to remortgage at the natural fix end and consider locking a longer fix if you expect rates to remain elevated.

Rate forecasts suggest near-term changes

Treat forecasts as informational only — the UK rate environment has surprised consensus repeatedly in 2024-2026. Don't time market entry on speculative forecasts. Act on actual current rates vs your actual current rate.

Property-value triggers

Significant value rise

If your property has risen 10%+ since the original mortgage, your LTV has dropped meaningfully. Check the current LTV band:

LTV band	Typical 2026 rate vs base
95%	+1.0-1.5pp
90%	+0.5-1.0pp
85%	+0.3-0.6pp
80%	+0.2-0.4pp
75%	+0.1-0.3pp
60%	Best rates

Crossing from 85% to 80% LTV typically saves 20-30 bps on the rate. On a £200k loan over 5 years, that's £1,200-£1,800 saved — usually enough to justify the remortgage cost even mid-fix if combined with a rate environment improvement.

Significant value drop

Wait for fix end. Switching to a higher LTV band locks you into higher rates. If your LTV has crossed into the 95%+ band, product transfer with existing lender may be the only viable route — they don't reassess your LTV.

Life-event triggers

Income drop or job change

Product transfer (no affordability check) is the safer route. Switching lenders may fail at affordability stage. Lenders typically want 6+ months in current role for new applications, so timing changes badly.

Becoming self-employed

Most lenders want 2-3 years' self-employed accounts. If you've just transitioned, plan a product transfer at the next fix end and target a switch 2 years later. See the self-employed mortgage guide.

New debt or credit issue

Product transfer skips the new credit check. Switching exposes the issue. Time application after 12-18 months of clean credit to maximise lender options. See how to improve your credit score for a mortgage.

Selling within 12 months

Don't remortgage. Either port the existing mortgage to the new property (cheaper) or repay at sale. Remortgage costs aren't recoverable in a 12-month window.

Releasing equity for home improvements / deposit elsewhere

Remortgaging to release equity adds to the mortgage balance — check affordability on the larger loan. The additional amount is usually at the same rate as the rest of the mortgage. Some lenders charge slightly higher rates on "further advances".

The no-ERC window in detail

Most UK fixed-rate mortgages allow:

• No-ERC overpayments: Up to 10% of the outstanding balance per year without penalty.
• No-ERC remortgage window: Last 3 months of the fixed period.

The 3-month window is the lever you should always plan around. A typical timeline:

1. Month -6: Start broker search, get AIPs.
2. Month -5: Submit full mortgage application with chosen lender.
3. Month -4: Receive mortgage offer.
4. Month -3: Instruct conveyancer; enter no-ERC window.
5. Month -2 to 0: Conveyancing progresses.
6. Day 0 (fix end-date): Completion. No ERC, no SVR, straight into new fix.

When to take a longer fix vs a shorter one

2-year fix

Lowest rates typically. Best if you expect rates to fall further, or if you're planning to move within 2 years (you'll remortgage or port anyway). Comes with the highest fee + admin frequency.

5-year fix

Slightly higher rate but rate certainty for longer. Best if you expect rates to rise or stay flat, and if you value the lower remortgage admin frequency. Comes with longer ERC exposure — be careful about planned life changes (job change, moving) within the 5-year window.

10-year fix

Highest rate but maximum certainty. Niche product — best for buyers who explicitly want to lock costs for the long term and won't move. Be very cautious about life changes during the 10-year window.

Tracker

Rate follows Bank of England base rate (or LIBOR-equivalent) with a margin. Best when base rate is expected to fall sharply. No ERC on most tracker products. Often used as a temporary step between fixes if rate environment is uncertain.

The remortgage diary — what to check annually

Even if you're mid-fix, run this annual review:

1. Months remaining on current fix
2. Current outstanding balance
3. Property value (Zoopla / Rightmove estimate as rough guide)
4. Current LTV (balance ÷ value)
5. Current rate vs market rates today
6. Any life changes affecting credit / income
7. Any planned life changes in next 12 months

Set a calendar reminder for month -6 of the fix to start the remortgage process. This is the single highest-value financial housekeeping habit for UK homeowners.

Decision tree summary

In one paragraph: if your fix expires within 6 months, start the remortgage process now. If your fix expires in 6-12 months, diarise month -6. If you're mid-fix (1+ years remaining), only break early when the saving over remaining fix exceeds (ERC + fees), which usually requires a 1.5+ percentage point rate drop with 3+ years left. In every other scenario, hold and monitor at annual review. Use the remortgage savings calculator to test the break-even maths against your specific balance, rate, and remaining term.

Frequently asked questions

When is the best time to remortgage?

At the natural end of your fixed-rate period — start 4-6 months before expiry. Avoids SVR and avoids ERC.

Should I remortgage before my fix ends?

Usually no — the ERC typically exceeds the rate saving. Break-even: rate saving × outstanding × years remaining must exceed (ERC + fees).

How early can I lock in a new rate?

Most lenders let you secure up to 6 months before completion. Many let you swap to better deals during that window if rates fall.

What if rates have dropped meaningfully?

1.5+ percentage points drop with 2+ years remaining — run break-even. ERC + fees should be less than rate saving × balance × years.

What if rates have risen since I fixed?

Stay put. Your rate is already lower than market. Plan to remortgage at fix end and consider longer fix.

Should I remortgage if my property value has risen?

Worth checking. If LTV has dropped 5+ percentage points, the rate band may have improved. Only lender's valuation matters.

What if my circumstances have weakened?

Product transfer with existing lender bypasses affordability check. Switching may fail if income or credit have deteriorated.

How often should I remortgage?

Most UK homeowners every 2-5 years matching fix length. Frequent remortgaging compounds fees; long fixes lock you in.

The most expensive timing mistake

Allowing your fix to lapse onto SVR is the single most expensive mistake. Every month on SVR typically costs £200-£500 on a typical mortgage — more than the entire year's saving from optimising product fees. The fix to this is purely administrative: diarise at month -6, get an AIP at month -5, complete on the day your fix ends.

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Last reviewed: 21 June 2026.