A separate poll of 1,000 adults from the bank unveils the reasons borrowers are overpaying.
The low return on savings emerged as a major factor for borrowers increasing their mortgage payments, with 80% of those polled stating this to be the case.
Some 37% of home owners are paying off extra on their mortgages because of the base rate falls.
Of those not overpaying, 24% of borrowers are choosing to defy the credit crunch and spend excess money on holidays and clothing.
Terry Jordan, head of mortgages at The Co-operative Bank, says: “Our internal data has shown a 50% increase in our mortgage customers making overpayments.
“It would appear that with interest rates now at a historic low, customers are recognising more than ever the benefits of making overpayments.
“Providing their mortgage allows the flexibility to overpay, at the current time it can make real financial sense for customers to make even small monthly overpayments, as these can really add up to a large difference over the lifetime of the mortgage.”