Bladder Capacity Calculator
Estimate expected bladder capacity for a child aged 1–12 as (age + 1) × 30 mL and compare a diary maximum voided volume without diagnosing it.
Use the Bladder Capacity Calculator
Patient Details
Results
Expected Capacity
Scope
Age-based estimate for context—not a measured maximum, diagnosis, catheter-fill target or adult-capacity prediction.
Your Measured Volume
These are reference estimates. Consult a clinician for medical decisions.
Enter an age from 1 to 12, then click Calculate.
Scope, privacy and sources
This is a pediatric age-based estimate, not an ultrasound volume calculator, adult-capacity prediction, diagnosis or treatment recommendation. Expected capacity, maximum voided volume, post-void residual and cystometric capacity are different measurements.
Your age and volume stay in this browser; this calculator does not submit or store them.
Formula and diary definitions: ICCS standardization report and Cambridge University Hospitals pediatric bladder diary.
Summary
Estimate expected bladder capacity for a child aged 1–12 as (age + 1) × 30 mL and compare a diary maximum voided volume without diagnosing it.
How it works
- Enter the child's age in completed years from 1 through 12.
- Optionally enter a measured functional bladder volume in mL or oz.
- The calculator applies the ICCS expected bladder capacity equation: (age + 1) × 30 mL.
- Results show expected capacity and the recorded volume as a percentage of that estimate; they do not label a diagnosis or a universal normal range.
Use cases
- Urologists assessing voiding diary data against age-appropriate norms.
- Clinicians reviewing a pediatric bladder diary alongside the wider assessment.
- Parents tracking a child's bladder development and toilet training milestones.
- Urology students learning the pediatric expected-capacity equation.
- Researchers comparing measured volumes from urodynamic studies to reference values.