I wouldn't use all your savings, as you never know what is around the corner, you may need ready cash in the future, so keep at least some of it liquid. after that, despite mortgage interest rates having gone up in the past year, they are still very low, you are probably paying in and around the 5% mark, with a little bit of careful planning you should be able to get a higher return than that. it depends really when you feel you will want access to the money, if you want a low risk option you will probably have to leave your money tied up in an investment for a few years to make returns high enough to warrent keeping on your mortgage. another consideration is how hard you are finding it to meet your monthy payments on the mortgage. you should maybe do a financial review with an advisor, and look at all your options, you deffinitly shouldn't have all that money sitting in a low interest account.