Most kidney stones pass on their own, but how quickly and painlessly that happens depends on what you do in the meantime. Stones smaller than 5 mm pass about 80–98% of the time without surgery, while stones 6 mm or larger drop to a 33% chance or less. The key factors you can control are fluid intake, pain management, and whether you talk to your doctor about medication that relaxes the ureter.
How Size Determines Your Odds
Stone size is the single best predictor of whether you’ll pass it naturally. A large European study tracking spontaneous passage over 20 weeks found clear cutoffs: stones 0–3 mm passed 98% of the time, 4 mm stones passed 81% of the time, 5 mm stones passed 65% of the time, 6 mm stones dropped to 33%, and anything 6.5 mm or larger passed only about 9% of the time.
If your stone is 5 mm or smaller, expect the strategies below to make a real difference. If it’s closer to 7 or 8 mm, your doctor will likely discuss procedures to break it up or remove it rather than waiting.
Drink More Water Than You Think You Need
High fluid intake is the most straightforward thing you can do. The goal is to produce 2.5 to 3 liters of urine per day, which typically means drinking at least 3 liters (about thirteen 8-ounce glasses) of water daily. That volume keeps a steady flow of urine pushing the stone downward through the ureter and into the bladder.
Spread your intake throughout the day, including before bed. If your urine looks pale yellow to clear, you’re in the right range. Dark urine means you need more. Water is ideal, but you can mix in citrus-based drinks. About half a cup of lemon juice concentrate diluted in water each day (or the juice of two lemons) increases urinary citrate, a compound that helps prevent new stones from forming while you’re working on passing the current one.
Pain Relief That Actually Works
Kidney stone pain comes from the ureter spasming around the stone, and it can be severe. Anti-inflammatory painkillers like ibuprofen and naproxen are more effective than opioid-based options for this specific type of pain. A Cochrane review found that patients taking anti-inflammatories achieved slightly greater pain reduction and were 25% less likely to need a second “rescue” dose of pain medication within an hour.
The side effect difference is striking. Only about 6% of patients on anti-inflammatories experienced vomiting, compared to nearly 20% of those given opioids. Since nausea already accompanies many stone episodes, avoiding a medication that triples your vomiting risk is a practical win. If you can tolerate anti-inflammatories (and don’t have kidney disease or stomach ulcer issues that contraindicate them), they’re the better first choice.
Medication to Relax the Ureter
Your doctor may prescribe a type of medication called an alpha-blocker, which relaxes the smooth muscle in your ureter and widens the passage for the stone. This approach, called medical expulsive therapy, has solid evidence behind it. A meta-analysis of nearly 6,000 patients across 55 trials found that alpha-blockers improved stone clearance rates by 49% compared to no treatment. For distal ureteral stones (the lower portion, closest to the bladder) under 10 mm, the stone-free rate jumped from 54% with no treatment to 73% with medication.
One trial comparing active medication to placebo was especially telling: 82% of patients on the alpha-blocker passed their stone within two weeks, versus just 30% on placebo. That’s a meaningful difference when you’re in pain and want the ordeal to end faster. These medications are inexpensive, generally well tolerated, and worth asking about if your stone is in the 4–8 mm range.
How Long the Process Takes
Most stones that are going to pass will do so within two to six weeks. The timeline depends on size and location. In one study tracking lower ureteral stones, about 28% of patients were stone-free after the first week, another 28% after two weeks, 11% after three weeks, and roughly 9% after four weeks. So the majority of successful passages happen within the first two weeks, with diminishing returns after that.
Six weeks is generally considered the upper limit for watchful waiting. If a stone hasn’t passed by then, and especially if it’s causing persistent pain, recurrent infections, or blocking urine flow, your doctor will typically recommend a procedure. Waiting too long with an obstructing stone risks permanent kidney damage.
Movement and Physical Activity
Staying active helps. Walking and light movement use gravity and vibration to nudge stones along the urinary tract. There’s no rigorous clinical trial proving that specific exercises speed passage, but the physics are straightforward: a stone sitting in a tube will move more when the tube and the body around it are in motion. Research using kidney models on roller coasters demonstrated that vibration and positional changes can dislodge stones from the kidney itself. While that’s not the same as a controlled study in patients, it supports the general principle that movement beats bed rest.
The practical advice: walk regularly, take stairs when you can, and avoid sitting still for long stretches. Even if the effect is modest, staying active also helps manage pain and keeps your digestive system working (important since pain medications can cause constipation).
What to Eat While You’re Passing a Stone
You might assume you should cut calcium from your diet, but the opposite is true. A randomized trial followed men with recurrent calcium stones for five years and found that those eating a moderate-calcium diet (about 1,200 mg daily) had more than 50% lower risk of stone recurrence than those on a restricted-calcium diet of 400 mg daily. The reason: dietary calcium binds to oxalate in your gut, preventing it from reaching your kidneys. Too little calcium actually increases stone risk.
Aim for 800 to 1,200 mg of calcium daily from food sources like dairy, leafy greens, and fortified foods. Calcium supplements, on the other hand, don’t offer the same protective effect because they’re not taken with meals and don’t bind oxalate at the right time. Reduce sodium and animal protein, both of which increase the calcium concentration in your urine and make stones more likely to form or grow.
Signs You Need More Than Home Treatment
Most stones pass with water, pain relief, and patience. But certain signs mean the stone needs professional intervention: fever or chills (which suggest infection behind the blockage), inability to keep fluids down due to vomiting, pain that doesn’t respond to over-the-counter medication, or blood in your urine that worsens rather than improves. A stone that completely blocks urine flow is a urological emergency. If you stop urinating or develop pain on both sides, get to an emergency room.
Stones that are too large, infected, or stuck will need to be removed or broken apart. The specific procedure depends on size and location, but the recovery from most modern stone treatments is measured in days, not weeks. Imaging with a CT scan (which detects over 95% of stones) can confirm your stone’s size and position, giving your doctor the information needed to recommend the right approach.