About this calculator
Scientific Accuracy
Based on the validated EQUIL2 algorithm from peer-reviewed scientific literature, ensuring reliable results for clinical and research applications.
Flexible Unit Systems
Supports both SI units (mmol/L) and original EQUIL2 units (mg/dL), with automatic conversion between systems for seamless workflow.
Comprehensive Analysis
Calculates supersaturation ratios for multiple stone types including calcium oxalate, brushite, hydroxyapatite and uric acid
Parameter Modeling
Explore how changing individual parameters affects stone risk with interactive modeling tools, helping to identify key factors in stone formation.
Easy Data Export
Copy results in multiple formats for reports, presentations, or further analysis, streamlining your research and clinical documentation workflow.
Color-Coded Results
Intuitive color-coded risk assessment for each stone type, providing immediate visual feedback on supersaturation levels for quick clinical interpretation and easy reference.
About EQUIL2
EQUIL2 Algorithm
This application calculates the saturation of ionic substances in urine based on:
- Sodium, Potassium, Calcium, Magnesium, Ammonia
- Chloride, Phosphate, Sulfate, Oxalate, Citrate
- pH and Urate
This application is intended for research use only.
References
The code is translated from EQUIL2 Visual Basic code based on:
Werness PG, Brown CM, Smith LH, Finlayson B. EQUIL2: A Basic Computer Program for the Calculation of Urinary Saturation. J Urol. 1985;134(6):1242-1244.
Source Code
The R package is available on GitHub:
https://github.com/billdenney/equil2Unit Systems
This application supports two unit systems for input parameters:
SI Units: mmol/L
The International System of Units, commonly used in scientific and medical contexts worldwide
Original Units: mg/dL
The units used in the original EQUIL2 algorithm as published by Werness et al.
You can switch between unit systems using the radio buttons at the top of the input panel. The application will automatically convert your values when switching between systems.
When using the Original EQUIL2 Units option, values are passed directly to the algorithm without conversion.
The core math and algorithm remain unchanged regardless of which unit system is selected.
Supersaturation Results
Supersaturation Ratio (SS): The ratio of the actual product of ion activities to the solubility product. Values > 1 indicate supersaturation (precipitation may occur), values < 1 indicate undersaturation (dissolution may occur), values ≈ 1 indicate equilibrium.
Negative Delta Gibbs (ΔG): The thermodynamic driving force for crystallization. Positive values (like +1.3) indicate a stronger tendency for crystal formation and higher risk. Negative values (like -0.6) indicate undersaturation and lower risk of stone formation. Measured in kcal/mol.
Risk Levels: Low Moderate High
No Results Available
To view results:
1. Enter your urine parameters in the sidebar
2. Click the 'Calculate' button
3. Results will appear here with risk assessment below
The calculator will determine supersaturation ratios for various stone types based on your input values.
Risk Assessment:
Calcium Oxalate Risk
Hydroxyapatite Risk
Uric Acid Risk
Calcium:Citrate Ratio
Urinary stone risk assessment
This ratio helps assess stone formation risk independent of supersaturation calculations. Values ≤0.25 indicate low risk, 0.25-0.5 moderate risk, and >0.5 high risk.
Export EQUIL2 Results
Export your calculation results in different formats for use in reports, presentations, or sharing with colleagues. Choose your preferred format, select which information to include, and copy or download the results.
Preview:
Input Values Summary
Copy and paste these values for your records or sharing:
R Code for Direct Use
The following code can be copied directly into R to reproduce these results:
EQUIL2 Algorithm
This application calculates the saturation of ionic substances in urine based on:
- Sodium, Potassium, Calcium, Magnesium, Ammonia
- Chloride, Phosphate, Sulfate, Oxalate, Citrate
- pH and Urate
This application is intended for research use only.
Unit Systems
This application supports two unit systems for input parameters:
- mmol/L - The International System of Units, commonly used in scientific and medical contexts worldwide
- mg/dL - The units used in the original EQUIL2 algorithm as published by Werness et al.
You can switch between unit systems using the radio buttons at the top of the input panel. The application will automatically convert your values when switching between systems.
Unit Conversions
The following conversions are applied when using SI units:
- Sodium: mmol/L (same in both systems)
- Potassium: mmol/L (same in both systems)
- Calcium: mmol/L in SI → mg/dL in EQUIL2
- Magnesium: mmol/L in SI → mg/dL in EQUIL2
- Ammonia: mmol/L in SI → ug/dL in EQUIL2
- Chloride: mmol/L (same in both systems)
- Phosphate: mmol/L in SI → mg/dL in EQUIL2
- Sulfate: mmol/L in SI → mEq/L in EQUIL2
- Oxalate: mmol/L in SI → mg/L in EQUIL2
- Citrate: mmol/L in SI → mg/L in EQUIL2
- Urate: mmol/L in SI → mg/dL in EQUIL2
When using the Original EQUIL2 Units option, values are passed directly to the algorithm without conversion.
The core math and algorithm remain unchanged regardless of which unit system is selected.
References
The code is translated from EQUIL2 Visual Basic code based on:
Werness PG, Brown CM, Smith LH, Finlayson B. EQUIL2: A Basic Computer Program for the Calculation of Urinary Saturation. J Urol. 1985;134(6):1242-1244. doi:10.1016/s0022-5347(17)47703-2
Source Code
The R package is available on GitHub: https://github.com/billdenney/equil2