Stages of Passing a Kidney Stone

Medically reviewed by Dr. Griffin M, MBBS, MS (General Surgery), MCh (Urology). Specialist in Urology, Andrology & Kidney Transplant Surgery | Last reviewed: September 2026 

Passing a kidney stone is very painful. Many people say the pain is even worse than the pain of childbirth. If your doctor has told you that you have a kidney stone, or if you are already going through the pain, you want to know two things: what will happen next, and when you should worry.

This guide explains the stages of passing a kidney stone in simple words. You will learn what happens in each stage, what pain and symptoms to expect, how long it usually takes, and when you must see a doctor right away instead of waiting.

Quick Answer

A kidney stone passes through five stages. First, it forms inside the kidney. Then it moves into the ureter (the thin tube that carries urine). It causes very sharp pain, called renal colic, as it travels through this tube. After that, it enters the bladder, where the pain becomes much less. Finally, it leaves the body through urine. Small stones (under 4–5 mm) usually pass on their own in one to three weeks. Bigger stones may need a doctor’s help to come out.

What is a Kidney Stone and Why Does It Form?

A kidney stone is a hard deposit made of minerals and salts that forms inside the kidney. It develops when certain substances in the urine become too concentrated and begin to form tiny crystals. Over time, these crystals can stick together and grow into a stone. Kidney stones can be as small as a grain of sand or, in rare cases, much larger.

Factors That Increase the Risk of Kidney Stones

Several factors can increase your chances of developing a kidney stone, including:

• Not drinking enough water, which makes the urine more concentrated
• Eating too much salt or animal protein, which can increase the risk of stone formation
• Eating large amounts of oxalate-rich foods, particularly if you are prone to calcium oxalate stones
• Health conditions such as obesity, diabetes, gout, or recurrent urinary tract infections
• Family history, as having a close family member with kidney stones can increase your risk
• Previous kidney stones, which can make you more likely to develop them again

The exact reason a kidney stone forms can vary from person to person. Understanding the factors that contribute to stone formation can help you take steps to reduce your risk of developing kidney stones in the future.

The Five Stages of Passing a Kidney Stone

Every stone is a little different, but most stones follow the same journey. Knowing which stage you are in can help you understand your pain and what will happen next.

Stage 1: The Stone Forms in the Kidney

This stage has no pain. Tiny crystals slowly build up inside the kidney. The kidney does not have many nerves that feel pain, so most people don’t notice anything until the stone starts to move. This is why many kidney stones are found only during a scan for some other health check.

Stage 2: The Stone Moves into the Ureter

When the stone leaves the kidney, it enters the ureter. This is a very narrow tube that carries urine from the kidney to the bladder. Because the ureter is so thin, even a small stone can block the flow of urine. This is usually when the pain starts. It may begin as a dull ache in your back or side and then slowly get worse.

Stage 3: Renal Colic – The Most Painful Stage

This is the stage that people usually mean when they talk about “passing a stone.” As your body pushes the stone through the ureter, the muscles squeeze tightly. This causes very sharp pain that comes and goes in waves. The pain can spread from your back to your lower stomach and groin. You may also feel nausea, vomiting, or notice blood in your urine, because the stone’s rough surface can scratch the inside of the ureter as it moves.

For most people, this is truly the hardest part, both in body and in mind. It can last from a few hours to several days, depending on the size and shape of the stone.

Stage 4: The Stone Reaches the Bladder

Once the stone enters the bladder, the sharp pain usually reduces quickly. The bladder is much bigger than the ureter, so the stone has more space to move without causing muscle spasms. Many patients say this is when they finally feel some rest. You may still feel like urinating often, as your body prepares to push the stone out.

Stage 5: The Stone Leaves the Body

In the last stage, the stone passes out through the urethra when you urinate. You may feel a slight stinging feeling. Often, you can actually see the small, hard stone in the toilet or in a urine strainer. It is also common to see a little blood in your urine for a day or two after this. This usually happens because of mild irritation and goes away on its own.

Does the Size of the Stone Matter?

Yes, size matters a lot. It is the biggest factor in deciding whether a stone will pass on its own, and how long it will take.

• Under 4 mm: About 80 out of 100 stones this size pass on their own, often within one to two weeks.
• 4–6 mm: About half pass without any treatment, but it may take two to three weeks.
• Over 6–7 mm: These stones rarely pass by themselves. Your urologist will likely suggest a procedure instead of waiting.

If you don’t know your stone’s size, check your CT scan or ultrasound report — it will be written in millimeters (mm). Ask your doctor to explain this number, because it decides your treatment plan.

How Do Doctors Check for a Kidney Stone?

If your symptoms point to a kidney stone, your doctor may use these tests:

• CT scan (without contrast dye) – The best way to find and measure the exact size of a stone
• Ultrasound – Often used for pregnant women, or when doctors want to avoid extra radiation
• Urine test – Checks for blood, crystals, or signs of infection
• Blood test – Checks how well your kidneys are working, and your calcium or uric acid levels

Getting the right diagnosis is important. It tells you and your doctor whether you can wait for the stone to pass naturally, or whether you need treatment right away.

How to Manage the Pain While the Stone Passes

If your doctor says your stone is small enough to pass on its own, these steps can help:

• Drink plenty of water. Try to keep your urine pale in color. This helps push the stone along and reduces irritation.
• Take pain relief medicine as advised. Medicines like ibuprofen often help with the sharp pain. But check with your doctor first, especially if you have kidney or stomach problems.
• Ask about medicine to help the stone move. For some stones, doctors give medicines called alpha-blockers, like tamsulosin. These relax the muscles of the ureter and can help the stone pass faster.
• Use a warm compress. Placing a warm cloth or heating pad on your back or stomach can ease muscle tension between painful episodes.
• Strain your urine. Catching the stone lets your doctor test what it is made of. This helps in planning how to prevent future stones.

When Does a Stone Need Treatment from a Doctor?

Not every stone can pass on its own. If a stone gets stuck for too long, it can damage the kidney or cause infection. Your urologist may suggest:

• Shock wave lithotripsy (SWL) – Uses sound waves from outside the body to break the stone into smaller pieces that can pass easily
• Ureteroscopy – A thin scope is passed through the urethra and bladder to remove or break the stone directly
• Percutaneous nephrolithotomy (PCNL) – Used for large or difficult stones. A small cut is made to reach the kidney directly and remove the stone

Warning Signs – When to Rush to a Doctor

Most kidney stones are very painful but not dangerous. However, some symptoms mean there is a serious problem that needs urgent care. Go to a doctor or hospital right away if you have:

• Fever or chills along with stone pain – this can mean a kidney infection, which is an emergency
• Not able to urinate at all
• Pain so bad that you cannot sit still or get any relief
• Vomiting so much that you cannot keep fluids down
• Heavy blood in urine, not just a light pink color

These signs don’t always mean something is seriously wrong. But they are not things to handle at home. See a doctor the same day.

Recovery After the Stone Has Passed

Once the stone comes out, most people feel much better within a few hours. Some mild soreness for a few days is normal, as the ureter and urethra heal from the irritation. A few things can make recovery take longer:

• Leftover small pieces of the stone can still cause mild irritation until they clear out
• Swelling in the urinary tract from the stone’s movement can take a few days to settle
• A urine infection, which can sometimes happen during the process, can cause pain that doesn’t go away, or gets worse

If your discomfort lasts more than one or two weeks, or if pain comes back months after the stone was passed or removed, get checked again. This could mean a new stone, leftover pieces, or scar tissue, and not the same old problem.

How to Prevent Future Kidney Stones

About half of people who get one kidney stone will get another one within a few years, unless they change their diet and drink more water. Here are some simple, proven steps:

• Drink more water – aim to produce at least 2 to 2.5 litres of urine a day
• Eat less salt – too much salt increases the calcium in your urine
• Get calcium from food, not tablets, unless your doctor tells you otherwise. Calcium from food actually binds with oxalate in your gut and can lower your stone risk
• Eat less meat if you tend to get uric acid stones
• Ask your doctor for a full metabolic test if you have had more than one stone. This helps find the exact cause so prevention can be planned properly

Final Thoughts

Passing a kidney stone can be very tiring, both for your body and your mind. But knowing what happens in each stage, and which symptoms are normal versus which ones need urgent care, can make the whole experience feel less scary. If your pain is not improving, or if you still have discomfort weeks or months after passing a stone, it is best to get checked by a doctor instead of just waiting it out.

Read also: Kidney Stone Specialist in Chennai