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SWL Success Calculator

Clear, patient-friendly education to help you understand kidney stones, SWL treatment, preparation, recovery, and prevention.

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Will Lithotripsy Work for You? Calculate Your Success Rate

Not all kidney stones are the same, and neither are the results of shockwave treatment. This calculator uses your specific scan details—like the size and hardness of your stone—to provide an estimate of how likely you are to be “stone-free” after your ESWL procedure. Use these results to start a more detailed conversation with your urologist about your treatment plan.

Understanding Your Results: What the Numbers Tell Us

The General Benchmark
While every case is unique, clinical literature generally cites these average success rates for different procedures:

  • SWL (Shockwave): Typically 60% to 85% for small-to-medium stones.
  • FURS (Laser): Typically 80% to 90% for medium stones.
  • PCNL (Keyhole): Typically 90% to 95%+ for very large stones.

Important: Why No Model is 100%
It is important to emphasize that there is no predictive model in current medical literature that can guarantee a 100% stone-free result. The human body is complex, and several “real-world” factors can influence your final outcome that a calculator cannot fully account for, such as:

  • The exact chemical composition of the stone.
  • The unique internal anatomy of your kidney.
  • How your specific tissue reacts to shockwave energy.

A high percentage indicates a strong likelihood of success, but it should be used as a guide for discussion with your urologist rather than a guaranteed outcome.

Will My Kidney Stone Treatment Work? — Lithotripsy Academy

Will My Kidney Stone Treatment Work?

Answer a few simple questions and get your personalised prediction for shock wave treatment — backed by published medical research. Free, instant, and no registration needed.

Based on 5 clinical studies 9,000+ patients studied
1
About You
2
Your Stone
3
Your Results
01 A little about you
This helps personalise your prediction. No registration or email needed at this stage.
BMI = weight(kg) ÷ height(m)². Calculate yours
How to find these values on your CT / radiology report
  • Stone size — written in millimetres (mm), e.g. "8 mm calculus" or "1.2 cm stone"
  • Stone location — described as kidney (upper/mid/lower calyx, renal pelvis) or ureter (upper, mid, lower)
  • Stone density (HU) — appears as a number next to "attenuation" or "Hounsfield units", e.g. "650 HU"
  • Skin-to-stone distance — may appear as "SSD" in mm. Only relevant for kidney stones, not ureteral stones
  • Cannot find a value? Leave it blank — the calculator will still work with fewer details
02 About your stone
Fill in as much as you can find from your CT or ultrasound report.
From your CT report in millimetres
CT From your CT report (optional — improves accuracy)
Leave blank if you cannot find these values. The prediction still works without them.
Where to find it: Look for "attenuation value" or "HU" on your CT report. Usually a number from 100–2000.
Where to find it: Sometimes labelled "SSD" on radiology reports. Only applies to kidney stones.
Not needed for ureteral stones — this measurement does not apply to your stone location.
Your estimated chance of stone clearance — single treatment session
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0%25%50%75%100%
What this means for you
Recommended next steps
    Important: This tool is for informational purposes only. It is based on published medical research models but does not constitute a medical diagnosis or treatment recommendation. Your urologist has access to your full clinical picture and should always guide your treatment decisions. Individual results may vary.
    How This Prediction Is Calculated
    This tool does not use a single formula from one study. It uses a combined prediction model built from four independent research studies involving over 9,000 patients. Each study identified which stone and patient factors most strongly predicted treatment success. The factors that appeared consistently across multiple studies were given the most weight in this calculator.

    Because no single published model covers all stone types and all patients, this combined approach gives a more balanced and generalisable prediction. However, it has not been tested as a combined model in a new group of patients — which is why this tool is for information only and your urologist's assessment always takes priority.
    When Is Shock Wave Treatment Less Likely to Work?
    Based on the research, these stone characteristics are associated with lower success rates. If any of these apply to you, ask your urologist about alternative treatments.
    Stone profile Why it is harder to treat Typical success rate
    Large stone in lower part of kidney The lower calyx drains poorly — even broken fragments can get stuck. Shock waves also have further to travel. 25–40%
    Very hard stone (high HU density) Some stones are made of very dense minerals (e.g. calcium oxalate monohydrate) that resist breaking up with shock waves. 20–38%
    Stone larger than 15 mm Larger stones require much more energy to fragment completely. Multiple sessions are usually needed and complete clearance is less likely. 30–45%
    Multiple stones Four or more stones means a much higher total stone burden. Each stone needs to be targeted and fragmented, reducing the overall clearance rate. 28–42%
    Stone deep inside a heavier body A higher BMI or large skin-to-stone distance means shock waves lose more energy before reaching the stone, reducing fragmentation. 25–42%
    Kidney swelling present (hydronephrosis) Significant kidney swelling affects how shock wave energy is distributed inside the collecting system, reducing fragmentation efficiency. 28–44%
    Several adverse factors combined When multiple risk factors apply together — e.g. large, hard, lower calyx stone in an older patient with high BMI — the predicted success rate drops significantly. <20%
    When Is Shock Wave Treatment Most Likely to Work?
    These profiles are associated with the best outcomes from shock wave treatment.
    Small ureteral stone
    ≤8 mm in the ureter — 75–90% success rate
    Small soft kidney stone
    ≤5 mm, low density — 78–92% success rate
    Stone at kidney/ureter junction
    ≤10 mm at UPJ — 72–85% success rate
    Single small kidney stone, healthy patient
    ≤8 mm, normal BMI, low HU — 74–88% success rate
    Success rate ranges are estimates based on the consensus model across realistic parameter combinations within each scenario. Actual outcomes depend on your specific stone composition, the type of lithotripter used, your surgeon's experience, and other clinical factors. Always discuss your individual prediction with your urologist before making treatment decisions.
    Clinical References
    The five published studies on which this prediction tool is based
    1. Wiesenthal JD, Ghiculete D, Ray AA, Honey RJD, Pace KT. A clinical nomogram to predict the successful shock wave lithotripsy of renal and ureteral calculi. Journal of Urology. 2011;186(2):556–562. AUC 0.75
    2. Kim JK, Ha SB, Jeon CH, et al. Clinical nomograms to predict stone-free rates after shock-wave lithotripsy: development and internal validation. PLoS ONE. 2016;11(2):e0149333. AUC 0.755 · n=3,028
    3. Yoshioka T, Ikenoue T, Hashimoto H, et al. Development and validation of a prediction model for failed shockwave lithotripsy of upper urinary tract calculi using computed tomography information: the S3HoCKwave score. World Journal of Urology. 2020;38:3267–3273. Externally validated AUC 0.71 · n=2,271
    4. Niwa N, Matsumoto K, Miyahara M, et al. Simple and practical nomograms for predicting the stone-free rate after shock wave lithotripsy in patients with a solitary upper ureteral stone. World Journal of Urology. 2017;35:1455–1461.
    5. Dogan HS, Altan M, Citamak B, et al. A new nomogram for prediction of outcome of pediatric shock-wave lithotripsy. Journal of Pediatric Urology. 2015;11(2):84.e1–84.e6. Paediatric model · n=383
    This calculator applies a consensus-weighted logistic regression model derived from the adult studies above (Wiesenthal, Kim, S3HoCKwave, Niwa). The Dogan 2015 paediatric model is applied separately for patients aged ≤16 years in the physician version of this tool. Predictions are estimates only and do not constitute medical advice.
    Lithotripsy Academy  ·  Patient Information Tool  ·  Not a substitute for medical advice