What size kidney stone requires surgery?

Kidney stone surgery is not determined by size alone. While stones smaller than 5 mm often pass naturally, stones larger than 6–7 mm are less likely to pass without treatment. Stones measuring 10 mm or more usually require a surgical procedure, especially if they cause severe pain, urinary blockage, infection, or reduced kidney function.

Many people believe that surgery depends only on the size of the kidney stone. However, urologists consider several factors before recommending surgery.

These include: 

• Size of the stone
• Location of the stone
• Severity of symptoms
• Whether urine flow is blocked
• Presence of infection
• Overall kidney function

Stones Smaller Than 5 mm

Most stones under 5 mm pass naturally with adequate hydration, medications, and regular follow-up. Surgery is usually not required unless complications develop.

Stones Between 5–10 mm

Stones in this range may or may not pass on their own. If the stone becomes stuck, causes severe pain, repeated infections, or fails to move after a reasonable period, your urologist may recommend minimally invasive treatment.

Stones Larger Than 10 mm

Kidney stones measuring 10 mm or more are much less likely to pass naturally. These stones commonly require procedures such as:

• ESWL for selected stones 
• URS (Ureteroscopy) for ureteric stones 
• RIRS (Retrograde Intrarenal Surgery) for many kidney stones 
• PCNL (Percutaneous Nephrolithotomy) for large or complex kidney stones 

Surgery May Be Needed Even for Smaller Stones

Sometimes even a small stone requires treatment if it:

• Completely blocks the ureter
• Causes unbearable pain
• Leads to repeated urinary tract infections
• Results in fever or signs of sepsis
• Affects kidney function
• Does not pass after conservative treatment

This is why treatment decisions should always be based on a complete medical evaluation rather than stone size alone.

SCI International Hospital / Dr. Gautam Banga

At SCI International Hospital, New Delhi, Dr. Gautam Banga, Senior Consultant Urologist and Andrologist, carefully evaluates the size, location, and impact of each kidney stone before recommending treatment. Whenever possible, conservative management is preferred for small stones. If surgery is required, he offers advanced minimally invasive procedures such as ESWL, URS, RIRS, and PCNL, helping patients achieve effective stone clearance with less pain, minimal scarring, and faster recovery.