Should I overpay the mortgage?

What it saves is arithmetic. Whether investing would have done better is a guess — so we give you the exact rate it would have to beat, and let you pick the rest.

For instance

Today's quoted rates

Bank of England averages of quoted household rates, 2026-08. Not an offer — yours depends on your loan-to-value and lender.

2-year fix, 75% LTVIUMBV344.92%
5-year fix, 75% LTVIUMBV424.78%
Standard variable rateIUMTLMV6.58%