Emergency patterns
Fever, rigors, sepsis features, suspected infected obstruction, anuria, or clinical deterioration with stone disease.
Educational urinary stone calculator
Urinary Stone Passage Calculator
Estimate whether a ureteric stone is likely to pass with observation or medical expulsive therapy (MET), and identify when kidney, ureter, or bladder stone symptoms should prompt urology review or emergency care.
Safety notice: This educational tool does not replace clinical assessment. Seek urgent medical care if there is fever or rigors with stone pain, confusion, faintness, inability to pass urine, uncontrolled pain, severe symptoms in pregnancy, or an unwell child.
Result guide
How to read the result
GreenObservation or MET may be reasonable
OrangeEarly clinical or urology review
RedEmergency assessment
Kidney stone pain and passage
Can this stone pass, or is urology review needed?
People with renal colic or a new ultrasound, X-ray, or CT report often want to know whether a kidney, ureter, or bladder stone can be observed safely. This calculator focuses on the practical question patients and clinicians commonly face: whether continued observation or medical expulsive therapy may be reasonable, or whether early urology review is safer.
The estimate is most useful for ureteric stones, where spontaneous passage depends strongly on stone size, location, symptom duration, pain control, infection risk, kidney function, and hydronephrosis.
General guide
Ureteric stone passage and review guide
This table gives a simple overview before using the calculator. It is not a substitute for clinical judgement, but it helps explain why stone size, location, symptom duration, infection, pain control, kidney function, and hydronephrosis change the recommendation.
| Finding | General implication |
|---|---|
| ≤5 mm lower ureter stone, symptoms less than 2 weeks, pain controlled | Observation or medical expulsive therapy may be reasonable if there is no fever, infection, kidney-risk factor, or concerning obstruction. |
| 6–10 mm ureter stone | Spontaneous passage is less predictable; early urology review is often appropriate, especially if symptoms persist. |
| Stone symptoms lasting 2–4 weeks | The chance of passage is falling; review is usually advisable to confirm progress and kidney safety. |
| Stone symptoms lasting more than 4 weeks | Residual chance of spontaneous passage is low; urology review for possible intervention is recommended. |
| Fever or rigors with stone pain | This may indicate infected obstruction and should be treated as an emergency pattern. |
| Moderate/severe hydronephrosis, raised creatinine, solitary kidney, pregnancy, or unwell child | Lower threshold for urgent clinical or urology review. |
For clinicians
When to refer a urinary stone case
Early urology input is usually appropriate when the probability of spontaneous passage is low, symptoms are prolonged, pain control is poor, or obstruction may threaten renal function.
Renal-risk patterns
Single functioning kidney, transplant kidney, CKD, raised creatinine, bilateral obstruction, or moderate/severe hydronephrosis.
Failed observation or MET
Persistent symptoms beyond 2–4 weeks, stone >10 mm, recurrent uncontrolled colic, or no evidence of stone progression.
Special situations
Pregnancy, children, frail older adults, immunocompromised patients, and cases where imaging or renal function is uncertain.
Common questions
Urinary stone passage FAQ
Can a ureteric stone pass without surgery?
Many small ureteric stones can pass without surgery, especially stones ≤5 mm in the lower ureter when pain is controlled and there is no fever, infection, kidney-function concern, or prolonged persistence.
When should kidney stone pain be treated as urgent?
Fever or rigors with stone pain, confusion, faintness, inability to pass urine, uncontrolled pain, severe symptoms in pregnancy, or an unwell child should prompt urgent medical care.
Does hydronephrosis always mean surgery?
No. Mild hydronephrosis can occur early with ureteric obstruction. Moderate or severe hydronephrosis, infection, abnormal kidney function, single kidney, or symptoms lasting several weeks need earlier review.
Does this calculator store my details?
No. It does not ask for name, phone number, address, or free-text medical details. The assessment is processed by this site and is not stored by this tool.
When review is advised
Book consultation
Need a urologist's opinion?
If the calculator suggests early review, or if symptoms persist despite medical expulsive therapy, a urologist can confirm stone position, obstruction, kidney function, and whether intervention is needed.
Medical review
Reviewed by a urologist
Reviewed by: Dr. Sumeet Karna, Consultant Urologist, Maya Metro Hospital, Dhangadhi, Nepal.
Last reviewed: 28 June 2026.
Basis: EAU, AUA, UAA, and NICE urinary stone guideline principles, adapted into a conservative educational calculator for patients and non-urologist clinicians.
References
- European Association of Urology. EAU Guidelines on Urolithiasis. Available from: uroweb.org/guidelines/urolithiasis
- National Institute for Health and Care Excellence. Renal and ureteric stones: assessment and management (NICE guideline NG118). Available from: nice.org.uk/guidance/ng118
- American Urological Association. Surgical Management of Kidney and Ureteral Stones. Available from: auanet.org stone surgery guideline
- American Urological Association. Medical Management of Kidney Stones. Available from: auanet.org medical management guideline
- Urological Association of Asia. Clinical guideline for urinary stone disease. Available from: PubMed record