Remortgage savings calculator
This UK-focused calculator compares two simple scenarios: staying on your current mortgage rate for the rest of your remaining term, versus switching to a new rate today. It estimates the current and new monthly repayment, the total interest remaining under each rate, and the overall saving after accounting for switching fees. It also shows a break-even point: the month where the monthly saving has repaid the upfront fees, which can help when comparing deals that trade a lower rate for a higher fee. Mortgages in the UK can have different fee structures, daily interest, and early repayment charges, so treat the results as indicative. Use them to shortlist options, then confirm the exact rate, fee treatment, and any ERCs with your lender or broker.
- Both scenarios use a fixed rate for the whole remaining term you enter.
- Interest compounds monthly (rate ÷ 12) and payments are monthly.
- Fees are treated as upfront costs for break-even and total savings.
- No early repayment charges, lender incentives, or product switches are included.
Your inputs
Compare staying on your current rate vs switching to a new rate, including fees.
Results
Amortisation comparison
| Checkpoint | Current payment | Current interest | Current balance | New payment | New interest | New balance |
|---|
- Current: —
- New: —
- Break-even: —
Assumptions and interpretation
Remortgage comparisons depend on rate, fees, term length, and whether your lender applies any early repayment charges.
This tool models both scenarios as standard repayment mortgages with a fixed rate over the remaining term you enter. It estimates monthly payments using a standard amortisation formula and sums the interest across the remaining months.
Fees are treated as one-off upfront costs. Total savings subtract those fees from the interest reduction, and break-even is calculated as fees divided by the monthly saving. If you extend the term, monthly payments may fall while total interest rises.
If you have an ERC on your current deal or incentives on the new deal (cashback, free valuation, legal fees), include them separately in your decision.
Worked UK example
Example only. Results depend on your exact lender terms and fees.
Suppose you have £185,000 remaining on your mortgage with 18 years left, and you expect to pay 5.49% from today. You compare switching to a 4.59% remortgage with a £999 product fee, keeping the same remaining term.
The new rate may reduce the monthly payment and lower total interest over the remaining term. The fee reduces the net saving, and the break-even month tells you how long you would need to keep the new deal before the monthly saving has covered the fee.
FAQs
Common questions about remortgage savings, fees, and break-even.
Does a lower rate always mean I’ll save money?
Not always. Product fees, other costs, and a longer term can offset the benefit. This tool shows net savings after fees so you can compare like-for-like.
How is the break-even month calculated?
Break-even is the upfront fees divided by your estimated monthly saving. If the new payment is not lower, there is no break-even point.
Does this include early repayment charges (ERCs)?
No. ERCs can be significant and vary by lender and product. If an ERC applies, include it in your decision alongside this comparison.
Are fees added to the mortgage balance?
This calculator treats fees as upfront costs. If you add a fee to the loan, your interest cost will be higher than shown.
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 does the opposite.
Is this accurate for UK mortgages?
It’s a useful estimate. Many UK lenders calculate interest daily and have product-specific fees and incentives. Use this as a comparison tool, then confirm the exact figures with the lender or broker.
Should I compare with a product transfer?
Yes. A product transfer can avoid some remortgage costs and can be quicker. Compare the rate, fee, and any incentives in the same way.