Kidney Stone Size Chart in MM and CM

Learn From Doctor Team
Learn From Doctor Team is made up of well-qualified doctors of different fields with brilliant academic results and professional careers. The article is written and reviewed by doctors of this specialty.


The kidney stone size chart indicates the types of renal stone, their size, shape, and composition.

Biological stones that are formed within the renal system are known as kidney stones. They are clinically termed Nephrolithiasis.

The prevalence of kidney stones is alarmingly increasing in the US population. There are multiple groups of causes behind the high prevalence of kidney stones.

The kidney stone size chart is important for the clinical evaluation of the patient condition and treatment plan.

This article discusses kidney stone size chart, composition, signs and symptoms, treatment, prevention, and many more.


What is a Kidney Stone?

Kidney stones are deposits that appear as a stone and are made up of minerals and salts within the kidney or renal system.

A kidney stone can form anywhere within the renal system and interrupt normal renal function.

Kidney stones usually form when the urine become so concentrated the minerals and salts have the chunks to stick together and form crystals.

Kidney stones can be extremely painful or expressed with mild pain according to the location. If the stone is small enough it can be passed through the urine if you drink enough water.

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What is Kidney Stone Size Chart?

A kidney stone size chart contains certain information such as size, shape, composition, and often the location of a kidney stone. This information is required for evaluating the patient’s situation end for the ideal treatment plan.

Stones of certain composition and certain size can be cleared through urine if a person drinks enough water. On the other hand, if the size is larger than a certain value then it cannot be cleared normally and may need surgical treatment.

So either way the kidney stone is secured helps the doctors to evaluate the status and choose the ideal treatment method.


Kidney Stone Size Chart in MM

Stone Size


Common Treatment

Less than 2 mm

No Symptoms

Naturally passes without any treatment

2 mm

No symptoms

Drinking enough water

3 mm

No Symptoms

Drinking enough water and rest

4 mm

Can be painful

Drinking enough water + NSAIDs

4 -7 mm

Painful Urination

Drinking enough water + NSAIDs

Larger than 7 mm

Painful Urination


Kidney Stone Size Chart in CM

Stone Size


Common Treatment

1 cm

Extremely painful


2 cm

Extreme pain and associated symptoms


3 cm or more

Severe condition

Percutaneous nephrolithotomy (PCNL)

Causes of Kidney Stone

There is no single cause of kidney stones. There are multiple risk factors and often reasons behind the formation of kidney stones.

Usually, the kidney contains some crystalloid contents that are diluted in the urine when the person drinks enough water. If the person is dehydrated then the crystalloid particles form crystals eventually over time that leads to stone formation.

There are other risk factors for stone formation such as taking certain drugs, obesity, any kidney or renal condition, etc.

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Kidney Stone Risk Factors

There are some risk factors for kidney stones that are associated with the prevalence of kidney stones.

Family History

Family history plays important role in the occurrence of kidney stones in both males and females. If the parents have a history of kidney stones then the offspring are more likely to develop a kidney stone.


Dehydration is a principal cause of kidney stones. The crystal contents of the urine stay diluted in the urine. If an individual is dehydrated then the crystalloid contents get the chance to form crystals and eventually lead to stone.

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Obesity is a prime risk factor for kidney stones. Obesity or excess fat deposition reduces the kidney’s work rate and it may lead to the formation of kidney stones in the renal tubules or anywhere in the renal system.

Particular Diet

Taking a high amount of salts particularly sodium salts in diet can be a risk factor for the formation of kidney stones. The salts and the metals are the principal contents of the kidney stone.

Taking excessive sodium content leads to salt deposition and eventually kidney stones.

Gastric Conditions

Certain gastric conditions and gastric surgery may lead to the deduction of absorption of calcium and other salts. And it will eventually lead to accumulation of the calcium and other salts and the formation of kidney stones.

A complete or partial gastrectomy is also a prime cause of kidney stones.

Certain Drugs

Certain trucks that modify the decision and absorption of the metals and salts that are responsible for Reynolds stones he’s also risk factors for renal stones.


Kidney Stone Signs and Symptoms

The sign & symptoms of kidney stones may vary from person to person. But there are some common signs and symptoms that occur in almost every individual they’re suffering from a kidney stone.

  • Severe or sharp pain from site to site
  • Pain below the ribs
  • Pain in the lower abdomen and the groin region
  • Pain during the urination

If the condition is more severe or medically important then you may experience the following symptoms;

Kidney stones symptoms Infographics
Kidney stones symptoms Infographics
  • Bleeding during micturition
  • Foul-smelling urine
  • Fever if any infection is present

Kidney Stone Treatment

The kidney stone treatment approach differs according to the size, shape, composition, and location of the stone.

Conservative Treatment

Conservative treatment of small stones includes nothing but paracetamol-like drugs. Small stones can pass through the ureter by drinking enough water without any medications that facilitate the excretion of stones.

The doctor often prescribes NSAIDs to relieve the pain associated with the stones. Small stones do not require much time to get out of the body through the ureter if you follow the instruction given by the doctors.

The instructions may include;

  • Drinking around 3 liters of water a day
  • Avoiding taking too much salt
  • Fresh lemon water or coconuts juice

The doctors often prescribe a class of drug name alpha-blockers and some other drugs to relieve the associated symptoms.


Minimally Invasive Surgical Treatment

Removing large stones from the kidneys or urinary tract is not a major operation nowadays. There are three common ways of removing large stones from the kidneys.

  • Shockwave lithotripsy (SWL)
  • Ureteroscopy
  • Percutaneous nephrolithotomy (PCNL)

Shockwave Lithotripsy (SWL)

In this technique, a powerful shockwave is used to destroy the large stones into small spaces, and eventually, that comes out with the urine.


It’s a long thin telescope-like instrument. That is introduced into the body through the urinary passage and the surgeon may remove the stones by gripping stones with this instrument or breaking this instrument into small pieces.

Percutaneous nephrolithotomy (PCNL)

In this technique it’s small incision is made on the back of your body where the kidneys are located. Then a telescope is passed to the stone and break it into small pieces to facilitate its removal.


Composition of Kidney Stone

  • Calcium Oxalate – Prevalence rate 80%
  • Calcium Phosphate – Prevalence rate <5%
  • Uric acid – Prevalence rate 10%
  • Struvite – Prevalence rate 10%
  • Cystine – Prevalence rate < 1%

Time Needed for Passing Kidney Stones

Size of kidney stones

Chances of passing naturally

Time required to pass naturally


Less than 2mm

About 80%

8 days (average)

Drinking enough water

2-4 mm

About 80%

12 days (average)

Drinking enough water


About 80%

31 days (average)

Drinking enough water


About 60%

45 days (average)

Drinking enough water + NSAIDs

Larger than 7mm

About 20%

12 months (average)



Cannot pass


Larger than 2cm

Cannot pass

How Small Stones Pass-Through Urine?

Small stones can pass through the urine without any treatment just by maintaining a proper lifestyle and drinking enough water. Following the instruction provided by the doctor can be helpful.

As we already mentioned in the chart 2-7 mm sized kidney stones can be passed through the urine naturally without any invasive treatment.

However, kidney stones sized more than 5 mm can be painful during the passage. In that case, your doctor may prescribe you some painkillers such as paracetamol.


Prevention of Kidney Stones

Some common lifestyle modifications may help you to reduce the risk factors of forming kidney stones.

Drinking Enough Water

Dehydration is one of the principal causes of kidney stones. Drinking enough water such as a minimum of 1.5 liters per day your urinary tract clean and flushes away the small stones if there are any.

Please do not drink a lot of water at a time, rather drink a small amount of water.

Avoid Excessive Salt Intake

Taking access amount of table salt is related to the formation of kidney stones. Reducing excessive table salt intake may help to reduce the prevalence of kidney stones.

Lose Weight

Maintaining a healthy lifestyle and balanced diet is important to lead a healthy life. Obesity is one of the common risk factors for kidney stones.

If your BMI is very high, lose some weight.



A kidney stone size chart is important to determine if the stones need to undergo surgical treatment or if they can pass without any treatment just by drinking and of water and maintaining a good lifestyle.

As you mentioned earlier stones smaller than 4 mm does not require any medication.

Even 4-7 mm kidney stones can be excreted through the urine, and a little discomfort can be relieved by NSAIDs.


Frequently Asked Questions (FAQs)

What size kidney stone is considered large?

Stone size of more than 5 mm is commonly considered as large.

What is the dangerous size of a kidney stone?

When stone sizes are more than 7 mm it requires different surgical procedures to get rid of it.

If the stone sizes are more than 3 cm then it’s the most dangerous one and requires Percutaneous nephrolithotomy (PCNL).

At what size is a kidney stone require surgery?

Usually, kidney stones larger than 7 mm stones require surgery.

Can you pass a 7 mm kidney stone?

The ideal size for passing stones through urine is up to 4 mm. Kidney stones larger than 4 mm hardly pass through the urine and often arise in painful situations.

When is a kidney stone an emergency?

Kidney stone emergency can arise due to multiple conditions such as;
·      Stone in the urinary bladder
·      Stone in the ureter blocking the passage of urine
·      Extreme pain and shock
·      Rupture of the ureter and bleeding from the tract

How can I reduce the size of my kidney stones?

Certain medications can be prescribed by your doctors to reduce the size of the stones so that they can pass through the urine.
Often these medications are not enough to reduce the size of the stones then the doctor used certain instruments to break the large stones into smaller ones so that they can pass through the urine.

Last Updated on November 15, 2022 by Learn From Doctor Team

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