Can a 7 mm kidney stone pass on its own?

Possibly — stones 5-10 mm pass spontaneously about half the time. A trial of passage (fluids, pain control, often tamsulosin) for 4-6 weeks is reasonable if symptoms are controlled. If it's still there at 6 weeks, most urologists intervene.

What size kidney stone requires surgery?

Generally stones over 10 mm, stones that haven't passed after 4-6 weeks, stones causing persistent obstruction or pain, and any stone with fever or infection require intervention (ureteroscopy or shockwave lithotripsy).

How long does it take to pass a kidney stone?

For stones that pass, the median time is 2-3 weeks, with most passing within 4-6 weeks. Stones smaller than 5 mm usually pass fastest; larger stones take longer or don't pass at all.

When should I go to the ER for a kidney stone?

Go to the ER for: fever or chills with a stone (infected obstruction is an emergency), inability to urinate, intractable vomiting, or pain that isn't controlled by prescribed medication. Stones in a solitary kidney or during pregnancy also need urgent care.

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Kidney Stones

Kidney Stone Size Chart: Can It Pass on Its Own?

Stone size is the strongest predictor of whether a stone passes without intervention. What the published size thresholds mean for passing, pain, and treatment.

Evidence reviewed & updated: 2026-08 — reflects the latest published trials and guidelines.

TL;DR

Stone size is the best single predictor of spontaneous passage: stones under 5 mm pass on their own about 70-80% of the time, 5-10 mm stones pass roughly half the time, and stones over 10 mm usually need intervention. Location matters too — stones in the ureter cause the pain and are the ones that block.

<5 mm: ~70-80% pass spontaneously within weeks

5-10 mm: ~50% pass — trial of passage is reasonable for many

>10 mm: rarely pass without intervention (surgery or lithotripsy)

Location: stones in the lower ureter are more likely to pass than those at the kidney-ureter junction

Passing time: median ~2-3 weeks for stones that pass; most pass within 4-6 weeks

Emergency signs regardless of size: fever, intractable vomiting, anuria, unrelenting pain

At-a-Glance Comparison

Criteria

Option A

Option B

Option C

Stone size

<5 mm

5-10 mm

>10 mm

Pass rate

~70-80%

~50%

Rare

Typical course

Watch, fluids, pain control

Trial of passage; tamsulosin helps

Ureteroscopy or lithotripsy

Follow-up

2-4 weeks

4-6 weeks

Surgical planning

The size thresholds

The published pass rates: under 5 mm — roughly 70-80% pass on their own (some studies report 90% for 1-4 mm stones). 5-10 mm — about 50% pass spontaneously. Over 10 mm — spontaneous passage is uncommon, and most require ureteroscopy or shockwave lithotripsy (SWL).

The number that matters is the largest diameter on CT. Stones are also graded by location: ureteral stones cause the classic colic and pass more readily from the distal ureter (near the bladder) than from the proximal ureter.

Timeline for passage

For stones that do pass, the median time is about 2-3 weeks; most pass within 4-6 weeks. Medical expulsive therapy (tamsulosin) can speed passage for stones 5-10 mm in the distal ureter and reduce the need for intervention.

If a stone hasn't passed in 4-6 weeks with persistent symptoms, intervention is usually offered — waiting longer has little benefit and risks renal colic recurrences and kidney damage from prolonged obstruction.

When size stops mattering — emergencies

Regardless of size, these are emergency situations: fever or chills with a stone (possible infected obstructed kidney — can become urosepsis), anuria (no urine at all), intractable vomiting, or pain unrelieved by medication. A blocked kidney with infection is a medical emergency requiring urgent drainage.

Also urgent: stones in a solitary kidney, stones with renal failure, and stones in pregnancy.

The Evidence

Trial / Source

Key Finding

Reference

Published pass-rate data (Coll DM et al. and meta-analyses)

Spontaneous passage correlates with size: ~70-80% for <5 mm, ~50% for 5-10 mm

Urology literature

AUA Surgical Management Guidelines

Ureteroscopy or SWL recommended for stones unlikely to pass (typically >10 mm or symptomatic >4-6 weeks)

AUA 2016/2021

Key Metrics

70-80%

Pass rate for stones under 5 mm

2-3 weeks

Median passage time

6 mm

The size where 'trial of passage' gets harder

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TL;DR

The size thresholds

Timeline for passage

When size stops mattering — emergencies

Also urgent: stones in a solitary kidney, stones with renal failure, and stones in pregnancy.

The Evidence

Trial / Source

Key Finding

Reference

Published pass-rate data (Coll DM et al. and meta-analyses)

Spontaneous passage correlates with size: ~70-80% for <5 mm, ~50% for 5-10 mm

Urology literature

AUA Surgical Management Guidelines

Ureteroscopy or SWL recommended for stones unlikely to pass (typically >10 mm or symptomatic >4-6 weeks)

AUA 2016/2021

Kidney Stone Size Chart: Can It Pass on Its Own?

TL;DR

At-a-Glance Comparison

The size thresholds

Timeline for passage

When size stops mattering — emergencies

The Evidence

Key Metrics

Explore the Product

Frequently Asked Questions

Related Topics

Kidney Stone Types: Calcium, Uric Acid, Struvite & Cystine

Kidney Stone Pain vs Back Pain: How to Tell the Difference

Kidney Stone Diet: What to Eat and Avoid

Ready to Transform Your Facility?

Kidney Stone Size Chart: Can It Pass on Its Own?

TL;DR

At-a-Glance Comparison

The size thresholds

Timeline for passage

When size stops mattering — emergencies

The Evidence

Key Metrics

Explore the Product

Frequently Asked Questions

Related Topics

Kidney Stone Types: Calcium, Uric Acid, Struvite & Cystine

Kidney Stone Pain vs Back Pain: How to Tell the Difference

Kidney Stone Diet: What to Eat and Avoid

Ready to Transform Your Facility?