Updated 28 August 2026
Remortgage Calculator UK
A lower headline rate does not always mean a cheaper mortgage. This calculator compares your current deal with a new one over the length of the new fixed period, including the product fee, legal and valuation costs and any early repayment charge, then tells you the month at which switching actually starts paying.
- Fees and ERC included
- True break-even month
- Saving over the deal period
- New LTV tier check
Compare your deals
Is switching worth it?
Saving over the new deal period
£0
Monthly difference
£0
Break-even point
n/a
Current payment
£0
On your existing rate
New payment
£0
On the new rate
Cost to switch
£0
Fee + legal + ERC
Your LTV
0%
Year by year over the new deal
| Year | Current deal cost | New deal cost | Cumulative saving |
|---|
Cumulative saving is net of the one-off switching costs, which are applied in full at the start.
When remortgaging makes sense
- Your fixed deal is ending. This is the big one. Rolling onto a standard variable rate averaging around 7% in August 2026 costs roughly £234 a month more than a new 5-year fix on a £200,000 balance. Start looking six months out, because most offers are valid for three to six months, so you can lock a rate early and still take a better one if rates fall.
- Your LTV has dropped into a new tier. Capital repayments plus house price growth may have moved you from 90% to 80%, which is a genuinely different pricing tier. Check your current LTV in the calculator above.
- You want to overpay and your current deal will not let you. Some products cap overpayments tightly; a new one may not.
- You need to borrow more. Extensions and loft conversions are usually cheaper funded through a remortgage than an unsecured loan, though it stretches the cost over decades.
When it does not
- You are mid-fix with a large early repayment charge. A 3% ERC on £185,000 is £5,550, and that has to be recovered before you are ahead. The break-even figure above accounts for it.
- Your balance is small. Below roughly £50,000, a £999 fee eats most of the rate saving. Look for fee-free products instead, even at a slightly higher rate.
- Your circumstances have changed. Recently self-employed, on probation, or with new credit problems? A product transfer with your existing lender usually needs no new affordability assessment, whereas a full remortgage does.
Product transfer vs remortgage. A product transfer means taking a new deal with your current lender, with no legal work, no affordability check and no valuation, and it completes in days. A remortgage means moving lender, which opens the whole market and usually gets a better rate, but requires a full application. Always get a product transfer quote first, then see whether the open market beats it by enough to justify the paperwork.
Remortgage questions, answered
How long before my fix ends should I start?
Six months. Most lenders will issue an offer valid for three to six months, so you can secure a rate early and protect yourself against rises. If rates fall before completion you can usually switch to the cheaper product with the same lender at no cost. Leaving it to the last month risks slipping onto the standard variable rate while paperwork completes.
Does remortgaging hurt my credit score?
A full remortgage involves a hard credit search, which causes a small temporary dip. A product transfer with your existing lender usually does not. Neither has a lasting effect if you keep up payments. Avoid making several full applications in a short period.
Can I remortgage with bad credit?
Often yes, but the rate will be higher and the lender list shorter. If your credit has deteriorated since you took the current mortgage, a product transfer with your existing lender is usually the safer route because it typically avoids a fresh affordability assessment. Speak to a broker who specialises in adverse credit before applying anywhere.
How long does a remortgage take?
Four to eight weeks from application to completion is typical for a full remortgage. A product transfer with your current lender can complete in a few days. Build the longer timeline into your planning so your new deal starts the day the old one ends.
Should I add the fee to the loan?
Only if you have to. A £999 fee added to a 21-year mortgage at 5.12% costs about £1,630 by the end because you pay interest on it for the full term. Paying it upfront is cheaper whenever you have the cash. The main mortgage calculator lets you compare both ways directly.