Kidney stones can be very painful and can take some time to pass. While there are some tips that help to let your doctor know whether you are able to pass the stone by yourself or if you will need some help (i.e., is the stone too large to be able to pass), the actual time that is needed until it passes is very specific to each person and a number of variables that are difficult to know for certain. The size of the stone can often be determined by imaging, in many cases including a renal ultrasound. There are some things that can be done to help pass the stone, such as increasing your hydration, but if it comes to a point that the stone is too large, it may be necessary to use other assistance. In some cases, the stone can be broken up from the outside and in other cases, the stone may have to be removed.