The time it takes to pass a kidney stone varies mainly based on the stone's size and location within the urinary tract.
- Small stones (less than 4 mm): About 80% pass naturally, typically within around 8 to 31 days, with some sources noting an average closer to 1 to 2 weeks
- Medium stones (4 to 6 mm): Around 60% pass on their own, usually taking about 12 to 45 days
- Large stones (greater than 6 mm): Only about 20% pass naturally, and it can take up to 12 months for those that do pass without intervention. Larger stones often require medical treatment or surgery
Location also affects passage time: stones closer to the bladder tend to pass faster than those near the kidney
. In general, most kidney stones that pass spontaneously do so within 1 to 6 weeks, with smaller stones passing more quickly and with less pain. If a stone does not pass within this timeframe or causes severe symptoms, medical evaluation and possible intervention are recommended
. Pain management and sometimes medications like alpha blockers can help facilitate stone passage and reduce discomfort during this period
