Data from Moneyfacts shows a typical 2-year deal has increased to 6.7%, up from 6.63% on Monday and 6.66% yesterday.
This record rate, the highest since the economic downturn in 2008, will mean that homeowners whose deals are ending soon will find themselves paying hundreds of pounds more each month.
The recent rise pushes the cost of 2-year mortgages slightly above the peak of 6.65% reached last autumn. This comes as a blow to homeowners who are already grappling with financial strains.
5-year fixes have also increased with an average rate of 6.2%, up from 6.17% on Monday.
The Bank of England has hinted at further interest rate hikes in the near future despite a slowing labour market, which could exacerbate this pressure on homeowners.
Some commentators have predicted that interest rates could top out at around 7%, signalling that the next rate rise could be the first of many.
