Why people remortgage, and when
Reasons can include securing a different rate or rate type, reducing payment risk, changing the term, borrowing for an evidenced purpose, or moving to a lender whose criteria better fit changed circumstances. A lower headline rate is not proof of a saving: a fee, ERC, higher balance or longer term can reverse it. Borrowing more also means more interest and a fresh affordability assessment.
Start reviewing roughly six months before the initial deal ends so there is time to obtain a redemption statement, check eligibility and reserve a rate where the lender permits. The right window is product-specific. A fixed, tracker or discounted deal may have an ERC until a stated date; request the exact figure and any penalty-free overpayment allowance. The separate fixed-deal-ending guide explains the follow-on-rate mechanics and is linked below rather than duplicated here.
Product transfer or remortgage?
| Route | What it is | Checks and trade-offs |
|---|---|---|
| Product transfer | A new product with the current lender, usually without changing lender security. | Often simpler and faster, and may involve no new affordability or valuation check, but the lender’s available range may not be the whole market. Confirm whether a credit/affordability check, fee, ERC, advice fee or new term applies. |
| Remortgage to another lender | A new mortgage repays the existing one and replaces it with a new lender/product. | Can widen choice, but normally requires application, affordability and credit checks, property/security assessment and legal work. Eligibility is not guaranteed. |
Ask for equivalent illustrations for both routes. Compare like with like: the same balance, repayment basis, remaining term, deal period and payment frequency. A lower monthly payment achieved by extending the term may cost more overall. A product transfer is not “free” merely because legal work is not required.
Costs, ERCs and paperwork
Obtain the current lender’s redemption statement and offer documents. Check the ERC on the proposed completion date, daily interest, exit/admin fee, mortgage-account balance and any overpayment charge. Ask the new lender or adviser for the product fee (paid upfront or added to the loan), valuation fee, legal fee, advice/broker fee, transfer costs and conditions. “Free legals” and “free valuation” are product terms, not universal rights; confirm what work is included and whether a cashback replaces a fee.
Typical evidence may include identity, address, income (payslips, accounts or tax documents), bank statements, existing mortgage statement, debts and expenditure, property and buildings-insurance details. A new lender may reassess affordability, credit history, LTV, property and income; a product transfer may have different checks. Tell the adviser/lender about changed employment, income, borrowing, dependants or property use. Never assume a valuation is a survey or that an agreement in principle is an offer.
Compare total cost, not just payment
Use the lender’s illustration and redemption statement. The examples below are independently checkable illustrations, not forecasts, quotes or recommendations. They use a capital-and-interest repayment mortgage and assume the stated rate remains fixed throughout the 24-month comparison; they exclude future rate changes, tax, insurance, overpayments, missed payments and any fee not listed. Payments are rounded to the nearest penny. Verify with the MoneyHelper mortgage repayment calculator and the lender’s illustration.
Scenario A — lower-cost transfer illustration
Assumptions: balance £180,000; 18 years (216 months) remaining; 24-month deal; fixed rate 4.50%; monthly repayment calculated as P × i ÷ (1 − (1+i)^−n), where P=£180,000, i=4.5%/12, n=216; product fee £999; legal £0; valuation £0; advice £0; ERC £0.
| Item | Calculation | Amount |
|---|---|---|
| Monthly payment | amortisation formula above | £1,217.38 |
| 24 scheduled payments | £1,217.3842927930286 × 24 | £29,217.22 |
| Product fee | stated assumption | £999.00 |
| Legal + valuation + advice fees | stated assumptions | £0.00 |
| ERC | stated assumption | £0.00 |
| 24-month cash cost (payments + listed fees) | £29,217.22 + £999 | £30,216.22 |
| Illustrative balance after 24 payments | same formula | £166,405.66 |
| Principal repaid | £180,000 − £166,405.66 | £13,594.34 |
| Illustrative 24-month borrowing cost | cash cost − principal repaid | £16,621.88 |
Scenario B — lower rate but switching-cost illustration
Assumptions: the same £180,000 balance, 18-year remaining term and 24-month deal; fixed rate 4.25%; product fee £1,499; legal £350; valuation £300; advice £500; ERC £1,800 payable on the comparison completion date. The ERC is deliberately stated as an assumption, not a typical percentage.
| Item | Calculation | Amount |
|---|---|---|
| Monthly payment | same amortisation formula, 4.25% | £1,193.74 |
| 24 scheduled payments | £1,193.738079762392 × 24 | £28,649.71 |
| Product fee | stated assumption | £1,499.00 |
| Legal + valuation + advice fees | £350 + £300 + £500 | £1,150.00 |
| ERC | stated assumption | £1,800.00 |
| 24-month cash cost (payments + listed fees) | £28,649.71 + £1,499 + £1,150 + £1,800 | £33,098.71 |
| Illustrative balance after 24 payments | same formula | £166,092.18 |
| Principal repaid | £180,000 − £166,092.18 | £13,907.82 |
| Illustrative 24-month borrowing cost | cash cost − principal repaid | £19,190.89 |
Reading the scenarios: B’s rate and payment are lower, and its illustrative balance is about £313.49 lower. Its cash outlay is £2,882.49 higher; after allowing for that extra principal reduction, its illustrative borrowing cost is £2,569.01 higher using the rounded table figures. The result changes if fees are added to the loan, the term changes, the ERC expires, or the deal lasts longer. Payments and calculator outputs are illustrations—not a promise of rate, approval, affordability or future saving.
Pitfalls and decision checklist
Avoid comparing only the initial rate; ignoring the follow-on rate; forgetting ERC timing; adding fees to the loan without including their interest; extending the term to make payment look smaller; assuming a free valuation is a survey; applying after circumstances changed without discussing it; or assuming a lender will accept the property, income or credit history.
Before choosing, record:
- What is the balance, repayment basis, LTV, remaining term and exact deal end/first ERC-free date?
- What follow-on rate applies, and when? See what happens when a fixed-rate mortgage ends, rather than repeating that guide.
- What are the product-transfer and remortgage rates, payments and total listed costs over the same period?
- What are the product fee, legal, valuation, advice, admin, cashback and ERC amounts, and when are they payable?
- Does either option change the term, overpayment allowance, portability, repayment basis, tracker formula or payment risk?
- Can the household afford the payment after the deal, and after a plausible rate rise if choosing a variable product?
- What evidence and affordability checks will be required, and has any circumstance changed?
- Have the lender’s illustration, redemption statement and final offer been checked by a regulated adviser or lender?