Why payment saving alone is incomplete
Two repayment mortgages with the same end date reduce capital at different speeds. This calculator tracks both monthly payments and remaining balances, then deducts the switching costs entered to find the first estimated break-even month.
What to include in switching costs
Include any early repayment charge, arrangement or product fee, legal work, valuation and broker fee that is not already reflected elsewhere. Adding a fee to the mortgage still has a cost and can also attract interest.
Important limitations
Rates are held constant for the comparison period. The result excludes fees added to the loan, cashback, overpayments, product reversion, tax and differences in insurance. It is not a recommendation or mortgage offer.
Reviewed by the Properties & Homes editorial team
Last reviewed: 14 August 2026.