How painful is it to pass a 1mm kidney stone?

Renal colic.: That's a very small stone, and should pass from the ureter into the bladder readily. That's not to say it won't get stuck along the way, and when these so tes get stuck they hurt a lot. Drinking a lot of water will make you produce a lot of urine, thereby dilating the ureter and facilitating the movement of this stone.

Usually minimal pain: Passing a 1 mm kidney stone often causes little or no pain. On occasion, however, it can be significantly painful. The pain is caused by blockage of the ureter between the kidney and the bladder. Passing the stone from the bladder out the urethra is usually not a problem.

Almost none, but...: A 1-mm stone is most likely still attached to the papilla of a calyx and its odd to detach and drop into ureter is very low. If happening, a 1-mm stone should have an almost 100% of chance to pass with no discernible pain. In reality, I would not spend much time to mull over it because it shades too little clinical significance to worry about it. Best wishes...