Enter Renal Inputs
Use adult mode for ages 18 and older. Use pediatric mode for ages 1 to 18 when height is available.
Example Data Table
These worked examples show how different profiles can affect estimated renal results.
| Case | Age | Sex | Creatinine | Cystatin C | Weight | Height | Primary estimate |
|---|---|---|---|---|---|---|---|
| Adult example | 52 | Male | 1.20 mg/dL | 1.00 mg/L | 78 kg | 175 cm | Combined adult eGFR around 79.2 |
| Adult low filtration example | 68 | Female | 1.80 mg/dL | 1.60 mg/L | 64 kg | 160 cm | Combined adult eGFR around 34.8 |
| Pediatric example | 12 | Male | 0.90 mg/dL | 1.10 mg/L | 40 kg | 145 cm | Multivariable pediatric eGFR around 68.5 |
Formula Used
This calculator combines several renal estimation methods so you can compare filtration and clearance from the same visit data.
- Adult eGFR, creatinine: CKD-EPI 2021 race-free equation using age, sex, and standardized serum creatinine.
- Adult eGFR, creatinine plus cystatin C: CKD-EPI 2021 combined equation when cystatin C is entered.
- Pediatric eGFR: Bedside Schwartz equation when height is available.
- Enhanced pediatric estimate: multivariable creatinine-cystatin C-BUN equation when height, cystatin C, and BUN are entered.
- Creatinine clearance: Cockcroft-Gault estimate for adults when weight is provided.
- Body surface area: Mosteller equation using height and weight.
- BUN / creatinine ratio: BUN divided by standardized serum creatinine.
CKD-EPI 2021 creatinine: eGFR = 142 × min(Scr/κ,1)α × max(Scr/κ,1)-1.200 × 0.9938Age × 1.012 if female.
CKD-EPI 2021 creatinine-cystatin C: eGFR = 135 × min(Scr/κ,1)α × max(Scr/κ,1)-0.544 × min(Scys/0.8,1)-0.323 × max(Scys/0.8,1)-0.778 × 0.9961Age × 0.963 if female.
Bedside Schwartz: eGFR = 0.413 × height(cm) / serum creatinine(mg/dL).
Cockcroft-Gault: CrCl = ((140 − age) × weight) / (72 × serum creatinine); multiply by 0.85 if female.
Mosteller BSA: BSA = √(height(cm) × weight(kg) / 3600).
How to Use This Calculator
- Select Auto, Adult, or Pediatric mode.
- Enter age, sex, and serum creatinine with the correct unit.
- Add cystatin C if you want the combined eGFR comparison.
- Add weight for Cockcroft-Gault clearance.
- Add height to calculate body surface area and pediatric eGFR.
- Add BUN to calculate the BUN / creatinine ratio and the enhanced pediatric estimate.
- Press Calculate Renal Function to show the result above the form.
- Review the detailed cards, stage range, and interpretation notes.
- Use the CSV or PDF buttons to save the output.
Frequently Asked Questions
1. What does eGFR estimate?
eGFR estimates how well the kidneys filter waste from blood. It is a calculated value, not a directly measured filtration test, so trends and clinical context matter.
2. Why does the calculator offer cystatin C?
Cystatin C can improve estimation accuracy in some adult cases. When supplied, the calculator shows a combined creatinine-cystatin C eGFR for comparison.
3. Is Cockcroft-Gault the same as eGFR?
No. Cockcroft-Gault estimates creatinine clearance in mL/min, while eGFR is usually indexed to 1.73 m² of body surface area.
4. Why is height optional for adults?
Height is not required for the adult CKD-EPI equations. It becomes useful when you want body surface area and BSA-adjusted clearance.
5. Can one low result diagnose chronic kidney disease?
No. Chronic kidney disease usually requires persistent abnormal findings over time or other markers of kidney damage. A single estimate is only one data point.
6. When should pediatric mode be used?
Use pediatric mode for children and adolescents when height is available. The bedside Schwartz estimate is a common rapid pediatric method.
7. Why does the calculator convert creatinine units?
Many labs report serum creatinine in mg/dL or µmol/L. Standardizing the input first keeps the formulas internally consistent.
8. Can I use this page for medication dosing?
Use it for education and preliminary review. Medication dosing, acute illness decisions, and urgent symptoms should be handled with a licensed clinician.