With a capped rate mortgage you pay the standard variable rate but your lender will set an upper rate - or cap. Your interest rate is guaranteed not to rise above this level for the period the cap is in place. You get the best of both worlds, in that the amount you pay will never rise beyond a certain amount for the period of the deal but it could fall if the lender's standard variable rate (SVR) falls during the period. The price you pay for this security is that deals may be less competitive than fixed and discounted rate mortgages. You can cap for a range of periods, from six months to five years.