Stable Numbers
Mortgage Refinance Calculator
Compare your current mortgage with a proposed refinance. Include upfront and financed fees, choose a new term, and see monthly saving, break-even time, total interest saved and an NPV view.
Current mortgage
You can mix years and months.
New deal
Fees (optional)
Arrangement, valuation or legal fees paid at completion.
These increase the balance and accrue interest.
Used to discount monthly savings when computing break-even by value.
Cash break-even is when cumulative monthly savings exceed upfront fees. NPV discounts savings and includes financed fees.
These figures assume fixed rates with monthly compounding and level repayments. Lenders may round at different stages which can move pennies. ERCs are not included. Check your offer for any early repayment charges.
About this calculator
Refinancing makes sense when the new total cost after fees is lower or when the monthly saving arrives quickly enough to justify the switch. This page shows both angles. It computes the current repayment using the standard annuity formula based on your APR and remaining term. It then computes the new repayment on the refinanced balance, which is the existing balance plus any fees you choose to add. Upfront fees are treated as cash out on day one. Financed fees join the balance and attract interest, so the repayment and total interest include them.
The break-even view comes in two flavours. The cash break-even looks at the monthly saving versus the upfront fees alone and tells you how many months it takes to recover that outlay. The NPV view discounts the full stream of monthly savings at a rate you choose, subtracts the net effect of fees, and reports the present value in today’s money. If NPV is positive the refinance creates value under your assumptions. You can also shorten or extend the term on the new deal. Shortening tends to cut total interest faster, while extending lowers the monthly payment but usually raises the total interest paid.
Use this for remortgaging decisions and product comparisons. For a complete picture always factor in any early repayment charges and the timing of product transfers. Treat results as a planning guide and check lender documents before committing.
Explore more in the finance tools hub.