The length of time needed to grill a steak depends on how thick the cut of meat. A rule of thumb to start with is about 6 to 9 minutes per side, or until the desired doneness. If you use a thermomenter it will read 145 for medium-rare, 160 for medium, and 170 for well. Do not cut into the meat to see if it is done. All the yummy jucies will run out.