Remortgaging means switching your existing mortgage to a new deal — either with your current lender (a "product transfer") or with a completely new lender (a "full remortgage") — usually without moving house. Most people do this as their fixed, tracker or discounted deal is coming to an end, so they can lock in a new competitive rate instead of automatically rolling onto the lender's standard variable rate (SVR), which is almost always more expensive. This calculator compares your current monthly payment against a new deal's monthly payment, shows your monthly saving (or extra cost), and works out how many months it takes to recover the new deal's fees.
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You're comparing staying on your current rate against switching to a new remortgage deal on the same outstanding balance (plus any additional borrowing you add). Remortgaging lets you avoid your lender's standard variable rate (SVR) and, if the new rate is lower, reduce your monthly outgoings.
Both monthly payments are calculated using the standard repayment mortgage formula, based on the balance, interest rate and term you enter for each scenario. The new deal's fees and any early repayment charge (ERC) are then compared against your monthly saving to work out how many months it takes to break even.
Your calculation summary will appear here once you enter your figures above.
This calculator provides an estimate based on a standard capital-and-interest repayment mortgage and does not account for interest-only balances, changing rates part-way through a term, product fees charged as a percentage that scale with the loan, or individual lender underwriting rules. It is provided for general guidance only and does not constitute financial advice — always get a personalised illustration from a mortgage broker or lender before committing to a new deal.
Remortgaging means replacing your existing mortgage with a new one on the same property, without moving house. You can remortgage with your current lender (often called a "product transfer" or "rate switch") or move to an entirely new lender (a "full remortgage"). Either way, the new mortgage pays off the old one and you continue making monthly payments under the new deal's rate and terms instead.
The most common reason is simply that a fixed, tracker or discounted deal is coming to an end, and the borrower wants to lock in a new competitive rate rather than drop onto the lender's standard variable rate (SVR). Other common reasons include: securing a lower rate than the current deal even mid-term (sometimes worth it despite an early repayment charge); releasing equity to fund home improvements, debt consolidation, or a deposit on another property; consolidating other, more expensive debts into the mortgage at a lower rate; or changing the mortgage type, term length, or lender for better service or flexibility.
Most lenders allow you to secure a new rate 3 to 6 months before your current deal ends, and many let you switch to a cheaper rate if one becomes available before completion, at no extra cost. Starting the process around 5-6 months ahead of your deal's end date gives enough time to shop the market, apply, get a valuation done, and complete exactly as your old deal expires — avoiding even a single month on the lender's SVR.
An ERC is a penalty charged by your current lender if you repay or switch away from a fixed or discounted deal before its agreed end date. It's usually calculated as a percentage of your outstanding balance, commonly tapering down each year — for example 5% in year one of a five-year fix, falling to 1% in the final year. ERCs don't apply once you reach the natural end of your current deal, so check your mortgage offer or annual statement for the exact percentage and the date it stops applying before switching early.
Most new deals charge a product or arrangement fee, commonly in the £0-£2,000 range, sometimes a flat amount and sometimes a percentage of the loan. You can usually pay this upfront in cash, or add ("capitalise") it onto your new mortgage balance. Paying upfront is normally cheaper overall, because capitalising the fee means you pay interest on it for the rest of the mortgage term — the longer your remaining term, the more that extra interest adds up, even though it feels more affordable month to month.
Loan-to-value is your mortgage balance as a percentage of your property's current value. As property prices rise, or as you pay down your balance (our mortgage overpayment calculator can model how extra payments speed this up), your LTV falls — and lower LTV bands (for example moving from 85% to 75% or 60%) often unlock noticeably cheaper rates at remortgage. It's worth getting an up-to-date valuation estimate before applying, since a property that's grown in value can move you into a better pricing tier even if your balance hasn't changed much.
If your property's value has grown, or you've paid down a significant amount of your mortgage, you may be able to borrow more than you currently owe and take the difference as a cash lump sum on completion — commonly used for home improvements, consolidating other debts, or raising a deposit for a second property. This is subject to the lender's maximum LTV for the purpose you state, a full affordability assessment, and usually comes with a higher rate than a simple like-for-like balance transfer, since you're borrowing more.
A product transfer stays with your current lender on a new deal — typically fast, with little paperwork, no new valuation, and often no fresh affordability or credit check, making it attractive if your circumstances have changed or you're short on time. A full remortgage moves you to a new lender, which can unlock a better rate or different features, but usually requires a full application, credit check, valuation, and sometimes legal work (though many deals include free standard legal and valuation services). Comparing both is worth doing every time your deal ends, rather than defaulting to whichever is easiest.
Say you have £180,000 outstanding, 20 years remaining, and your fixed deal has just ended, leaving you on an SVR of 7.5% — that's a monthly payment of around £1,450. A new deal at 4.8% over the same 20-year term brings the payment down to around £1,168 a month, a saving of roughly £282 a month. With a £999 arrangement fee and no ERC, you'd recover that fee from the saving in under 4 months, and be roughly £2,384 better off over the first year alone.
This tool assumes a standard capital-and-interest repayment mortgage at a constant rate for the full term entered — it doesn't model interest-only balances, rates that change again partway through (for example a 2-year fix inside a 25-year term), percentage-based fees that scale with a larger loan, or stamp duty and other costs unrelated to the mortgage itself. For a full, personalised comparison, speak to a mortgage broker or your lender directly.