Calculator
Large screens show three columns, smaller screens show two, and phones show one.
Example data table
These example records show how different equations can produce different estimates from different marker combinations.
| Mode | Age | Sex | Creatinine | Cystatin C | Height | ACR | Estimated eGFR | Interpretation |
|---|---|---|---|---|---|---|---|---|
| Adult creatinine | 52 | Female | 1.10 mg/dL | — | 165 cm | 18 mg/g | 60.5 mL/min/1.73 m² | G2 with A1 input |
| Adult combined | 67 | Male | 1.80 mg/dL | 1.50 mg/L | 174 cm | 120 mg/g | 43.7 mL/min/1.73 m² | G3b with A2 input |
| Adult cystatin C | 41 | Female | — | 0.95 mg/L | 160 cm | 25 mg/g | 83.7 mL/min/1.73 m² | G2 with A1 input |
| Pediatric bedside Schwartz | 12 | Male | 0.80 mg/dL | — | 150 cm | 18 mg/g | 76.9 mL/min/1.73 m² | G2 with A1 input |
Formula used
The calculator offers four commonly used equation paths, depending on the patient group and available laboratory marker set.
Adult creatinine equation
eGFR = 142 × min(SCr/κ,1)^α × max(SCr/κ,1)^-1.200 × 0.9938^Age × 1.012 if female
κ = 0.7 for females and 0.9 for males. α = -0.241 for females and -0.302 for males.
Adult combined equation
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 × 0.9961^Age × 0.963 if female
This path uses both creatinine and cystatin C, which can improve precision when both laboratory results are available.
Adult cystatin C equation
eGFR = 133 × min(Scys/0.8,1)^-0.499 × max(Scys/0.8,1)^-1.328 × 0.996^Age × 0.932 if female
This option is helpful when creatinine alone may be affected by muscle mass or body composition.
Pediatric bedside Schwartz
eGFR = (0.41 × height in cm) ÷ serum creatinine in mg/dL
This pediatric option requires height and creatinine. It also supports optional ACR and body surface area interpretation.
How to use this calculator
- Select the equation mode that matches the age group and the laboratory markers available.
- Enter age, sex, and the required marker values. Use the correct creatinine unit.
- Add height for the pediatric equation, and optionally add weight for absolute GFR.
- Enter urine albumin-creatinine ratio if you want albuminuria staging and a combined risk flag.
- Press Calculate eGFR to show the result card above the form.
- Review the equation label, eGFR value, stage, risk interpretation, and supporting notes.
- Download the result as CSV or PDF when you need to save or share the summary.
- Use repeated testing and clinical judgment rather than a single number alone for decisions.
Interpretation notes
GFR categories
- G1: 90 or higher
- G2: 60 to 89
- G3a: 45 to 59
- G3b: 30 to 44
- G4: 15 to 29
- G5: below 15
Albuminuria categories
- A1: below 30 mg/g
- A2: 30 to 300 mg/g
- A3: above 300 mg/g
Persistent changes over at least three months are important when classifying chronic kidney disease.
FAQs
1) What does eGFR estimate?
eGFR estimates how well the kidneys filter blood after adjusting for standard body surface area. It is a screening and monitoring metric, not a complete diagnosis by itself.
2) Why are there several equation modes?
Different equations suit different patients and lab data. Adults commonly use creatinine, cystatin C, or both, while children often use a height-based Schwartz estimate.
3) Why enter creatinine units carefully?
The formulas require creatinine in mg/dL. This calculator converts µmol/L automatically, but choosing the wrong unit can change the result substantially.
4) What is the benefit of adding cystatin C?
Cystatin C can improve estimation when creatinine may be influenced by muscle mass or body composition. When both markers are available, the combined adult estimate is often more informative.
5) Why is urine ACR optional?
eGFR measures filtration, while urine albumin-creatinine ratio reflects albumin leakage. Using both helps create a fuller chronic kidney disease risk picture.
6) What does absolute GFR mean?
eGFR is normalized to 1.73 m² of body surface area. Absolute GFR rescales the estimate to the patient’s own body size when height and weight are entered.
7) Can one result diagnose chronic kidney disease?
No. Chronic kidney disease classification usually depends on persistent abnormalities over at least three months, along with clinical context, labs, imaging, and medical review.
8) When should this tool be used cautiously?
Use caution in acute illness, unusual body composition, or situations where measured GFR or specialist review may be more appropriate than an estimating equation alone.