Decision one
What changes the result most?
The new rate, fees, remaining term and how long you expect to stay on the deal. That is usually where the decision is won or lost.
Mortgage strategy
Remortgage savings calculator
Use this calculator to see exactly whether a remortgage lowers your monthly payment, reduces total interest enough to justify the fees, and how long it takes to recover the switching cost.
What matters most
- The new rate, fees, remaining term and how long you expect to stay on the deal.
- Rate-shopping without looking at fees or the reset of the term often gives a cleaner-looking deal than the one you actually receive.
- Test the next move properly by comparing rate cut vs fees paid, then keep term vs extend term.
Decision two
Where does the estimate flatter the plan?
Rate-shopping without looking at fees or the reset of the term often gives a cleaner-looking deal than the one you actually receive. A neat output can hide that until you push the inputs harder.
Decision three
What should you compare next?
Run the base case, then compare rate cut vs fees paid, keep term vs extend term, and remortgage now vs wait. That usually tells you more than staring at one answer.
Before you calculate
Check whether the remortgage comparison works under normal life, not just under tidy assumptions
The point of this calculator is to show what really changes the outcome. For a remortgage, the biggest drivers are the new rate, the fees, the remaining term and whether you are keeping the term steady or stretching it out.
Run one version that reflects the deal you expect, one slightly tougher version, and one that assumes the savings are less generous. If the switch only works in the kindest version, the case for remortgaging is weaker than it looks.
Calculator
Model the decision before you live with it
Use figures you could keep up with in an ordinary month. The value here is not prediction for its own sake. It is about testing whether the plan still looks sensible once the easy assumptions are stripped out.
Calculator
Compare staying on your current deal with switching to a new rate, including fees and any term change.
Results
Your estimated remortgage summary appears here after calculation.
Remortgage snapshot
—
After fees, switching would change your monthly payment by —.
Net saving
—
Potential saving—
Fees—
Keeping your current deal would mean —. Switching would mean —. The break-even point is —, based on the fees entered and the estimated monthly payment difference.
Interpret the result
What this result is actually telling you
The headline number matters, but it is rarely the whole story. With a remortgage, you need to read the saving alongside the trade-off underneath it: fees paid now, the break-even point, and any extra cost created by extending the term.
This output becomes useful when you compare it with a harder version. If the saving disappears once fees are included, or only works because the term is extended, the plan is less attractive than the headline suggests.
Ask one direct question: would I still switch if the monthly saving was smaller than expected? That usually separates a genuinely strong remortgage from one that only looks good on the first pass.
Worked example: stay put vs remortgage
Take a £185,000 balance with 18 years left to run.
Scenario A: stay on 5.49%. Monthly payment about £1,459, with roughly £130,100 interest left over the remaining term.
Scenario B: switch to 4.59% with £999 fees and keep the same term. Monthly payment about £1,372, with roughly £111,400 interest plus the £999 fee.
That cuts the payment by about £87 a month and saves roughly £17,700 overall after fees.
What your results mean
If the monthly payment falls but the total saving is thin once fees are included, the deal is less compelling than it first appears. If the saving only exists because the term is longer, you are swapping short-term relief for higher lifetime cost.
What to do next
- If the saving is strong and the break-even point is early, the switch is usually worth serious consideration.
- If fees absorb most of the benefit, compare a product transfer or waiting for a better rate rather than forcing the switch now.
- If extending the term is the only way to create a saving, test whether keeping the current term gives a cleaner result.
When to take further action
If the current payment is becoming difficult, if you are approaching a higher revert rate, or if the mortgage only remains affordable by extending the term sharply, it is worth reviewing the wider structure with a broker or lender before the pressure builds.
When the answer looks cleaner than the reality
- When rate-shopping without looking at fees or the reset of the term often gives a cleaner-looking deal than the one you actually receive.
- When the result only looks strong because the easiest assumption was left untouched.
- When one headline figure distracts you from the actual cost or strain in the plan.
- When you treat a clean estimate as a promise rather than a planning tool.
Compare next
Compare the versions that answer the actual question
Put these side by side and see which one changes the outcome in a way you would actually feel, not just in a spreadsheet sense.
Rate cut vs fees paid?
This is the core remortgage test. A lower rate is useful only if the fee bill does not swallow the benefit. A cleaner headline rate can still be a weak switch if the recovery period is too long.
Keep term vs extend term?
Extending the term often lowers the monthly payment, but it can also increase total interest materially. Keeping the same term gives the cleaner comparison if you want to know whether the new deal is genuinely better.
Remortgage now vs wait?
If a better deal is available soon, waiting can be sensible. If the current rate is already expensive and the break-even point is short, delaying can cost more than it saves.
What this page cannot decide for you
It cannot predict the exact rate you will be offered, lender criteria, incentives, valuation results or early repayment charges. It is best used to rule out weak remortgage options, not to pretend one estimate settles everything.
How to get a cleaner answer from it
Run three versions: the deal you expect, a tougher version with slightly weaker savings, and a version that keeps the term unchanged. That usually tells you more than hunting for one perfect number.
FAQ
Remortgage savings calculator questions people actually ask
Does a lower rate always mean I’ll save money?
Not always. Product fees, legal costs, valuation charges and a longer term can offset the benefit. The rate matters, but the useful comparison is the net result after costs.
How is the break-even month calculated?
Break-even is the point where the monthly saving has repaid the upfront fees. If the new payment is not lower, or the saving is tiny, the break-even point may be too late to make the switch worthwhile.
Does this include early repayment charges (ERCs)?
No. ERCs can be significant and vary by lender and product. If one applies, it can change the decision quickly, so include it alongside this comparison rather than treating it as a minor extra.
Are fees added to the mortgage balance?
This calculator treats fees as upfront costs. If you add a fee to the loan, the balance increases and the real interest cost will be higher than shown here.
What if I change the term when I remortgage?
Extending the term usually lowers the monthly payment but increases total interest. Shortening the term usually raises the payment while cutting the total borrowing cost. That trade-off should be explicit in the decision.
Is this accurate for UK mortgages?
It is a useful estimate. Many UK lenders calculate interest daily and have product-specific fees, incentives and criteria. Use this as a comparison tool first, then confirm the exact figures with the lender or broker.
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