A kidney stone can take anywhere from minutes to hours. It all depends on size, how much liquids you can drink and most importantly, how much you can relax your body to allow it to pass. Kidney stones are very painful so the body tenses up causing constriction. This does not allow a little tiny stone to pass through the kidney very easily because it feels like it is a boulder, especially as it is going down through the ureter. Unfortunately, kidney stones are slightly sharp and that causes a lot of pain even though they are really tiny. They are so tiny that the doctor's office will many times give you a strainer that is even thinner than a cheese cloth to strain your urine through to try to collect the stone to make sure it passes. Kidney stones are caused by calcium in the kidneys and some people produce more than others. So, the more clear fluids you can drink the better because it will help to flush the kidneys forcing the stone out and cleaning the kidneys at the same time. Relax and let it go!