Product fees can be added to the overall value of the remortgage, but early repayment charges cannot.
The mutual said this would give switching clients who do not require further borrowing more options and wider access to its range.
It also said it would allow it to lend to more customers.
Jonathan Stinton (pictured), head of intermediary relationships at Coventry Building Society, said: “It’s a challenging environment for many borrowers, and we know how important some flexibility can be.
“The change to our stress rate in like-for-like remortgages will improve access to our remortgage products while maintaining our prudent approach to lending.”