Find out how much you could save by switching to a new mortgage deal. Enter your current rate and a new deal to see your monthly saving, total saving over the term, and how quickly the new deal pays back any fees.
Last updated: April 2026
Mortgage details
Your current mortgage
New deal
For a like-for-like comparison, keep the term the same. Extending the term reduces monthly payments but increases total interest.
Fees & costs
Typical: £0–£2,000
Check your mortgage offer or statement
Your remortgage summary
Monthly saving
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Enter your details to calculate
Current monthly payment -
New monthly payment -
Total switching costs -
Net saving over deal term -
Breakeven point -
Fee payback progress
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Side by side
Current
New deal
Rate
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Monthly payment
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Total interest
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Total paid
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How the remortgage savings calculator works
This calculator uses the standard mortgage amortisation formula to compute your monthly payment under both your current rate and a new deal, across the same outstanding balance and remaining term. The monthly saving is the difference between these two payments. The net saving over the deal term deducts all switching costs - arrangement fee, early repayment charge, valuation fee and legal fees - from the gross saving to give you the true financial benefit of switching.
The breakeven point tells you how many months it takes for your cumulative monthly savings to exceed the total upfront costs of switching. If you plan to move house or remortgage again before that point, switching may not be worthwhile even if the headline saving looks attractive.
When is the right time to remortgage?
Most fixed-rate mortgage deals last two to five years. When your deal ends, your lender will move you onto their Standard Variable Rate (SVR), which is typically 1.5 to 3 percentage points higher than the best available fixed rates. This is the most common reason to remortgage - you are no longer on a competitive rate and switching can save hundreds of pounds per month.
You should typically start looking at new deals around three to six months before your current deal expires. Many lenders allow you to secure a new rate in advance, meaning you can lock in a rate now even if the switch does not take effect for several months. This is particularly valuable when rates are rising.
Understanding early repayment charges
If you remortgage before your current deal expires, you will almost certainly face an early repayment charge (ERC). These are typically calculated as a percentage of your outstanding balance - commonly 1 to 5% - and taper down the closer you are to the end of your deal. For example, a deal with a 5% ERC in year one might reduce to 4% in year two, 3% in year three, and so on.
An ERC of even 1% on a £200,000 balance is £2,000. This calculator adds your ERC to the total switching costs so you can see clearly whether the saving justifies the penalty. In most cases, it is better to wait until your deal expires unless the rate differential is very large or you have several years remaining at a high rate.
Fees you should include
The true cost of remortgaging includes more than just the arrangement fee. Common costs to factor in are: the product or arrangement fee (which may be added to the mortgage, though this means you pay interest on it), a valuation or survey fee (typically £200 to £500 depending on property value), solicitor or conveyancing fees (typically £300 to £800 for a straightforward remortgage), and any broker fee if you use a mortgage adviser. Some lenders offer fee-free deals with a slightly higher rate, and our comparison shows you the total cost of the term rather than just the monthly payment, so you can weigh up that trade-off properly.
Extending versus matching your remaining term
When you remortgage, you can choose to keep the same remaining term, extend it, or shorten it. Extending the term reduces your monthly payment further but significantly increases the total interest paid over the life of the mortgage. Shortening the term increases monthly payments but clears the debt faster and at lower total cost. This calculator defaults to matching the remaining term for a like-for-like comparison, but you can adjust the new deal term to model different scenarios.
Frequently asked questions
The saving depends on the gap between your current rate and the new rate, your outstanding balance, and the remaining term. A borrower with £200,000 outstanding at 6.5% who switches to 4.5% on a 22-year term would save around £230 per month - approximately £2,760 per year and over £13,000 across a five-year deal period, before fees. For larger balances or bigger rate differences the savings are proportionally greater. Use this calculator with your own figures for an accurate answer.
The Standard Variable Rate (SVR) is your lender's default rate, applied automatically when your fixed, tracker or discount deal expires. Unlike your deal rate, the SVR is set by the lender and can be changed at any time, though in practice it tends to track the Bank of England base rate loosely. SVRs are typically 5 to 8% in the current environment - significantly higher than the best available fixed rates. Every month you spend on the SVR without acting is money you do not need to spend. If you are currently on your lender's SVR, remortgaging is likely to produce an immediate saving.
Most lenders allow you to add the arrangement fee to your mortgage balance rather than paying it upfront. This avoids an immediate cash outlay but means you pay interest on the fee for the remaining mortgage term. On a £999 fee at 4.5% over 22 years, the total interest cost of adding the fee to the mortgage rather than paying it upfront is approximately £670. Whether it makes sense depends on your cash flow - if you have the cash available, paying upfront is cheaper overall. This calculator assumes fees are paid upfront; if you are adding them to the mortgage, the monthly saving shown will be slightly smaller in practice.
Yes, a solicitor or licensed conveyancer is required to handle the legal transfer of the mortgage charge from one lender to another. However, many lenders offer a free legal service as part of their remortgage package, which covers the basic conveyancing work. If you are staying with the same lender and just switching products, no legal work is required - this is a product transfer rather than a remortgage, and it is simpler and cheaper. If you are borrowing more (further advance) or changing the names on the mortgage, additional legal work will be needed.
Lenders price mortgage rates by loan-to-value (LTV) bands - typically 60%, 75%, 80%, 85%, 90% and 95%. The lower your LTV, the better the rate you are likely to be offered, because the lender has more security. If your property has increased in value since you took out your original mortgage, your LTV may have fallen significantly, which could unlock a more competitive rate band. For example, a borrower who took out a 90% LTV mortgage five years ago might now be at 70% LTV through a combination of repayments and house price growth, qualifying them for substantially better rates. It is worth checking your current LTV before approaching lenders.
A whole-of-market mortgage broker has access to deals that are not available directly to consumers, and can advise on which lenders are most likely to accept your application based on your income, credit history and property type. Many brokers charge no fee to the borrower (they receive a procuration fee from the lender), though some charge an advice fee of £300 to £500. For straightforward remortgages where you have a clean credit history and standard employment, the benefit of a broker is mainly time-saving and access to exclusive deals. For more complex situations, a broker's guidance can be invaluable and save significantly more than their fee.