eGFR CKD-EPI 2021 Calculator - Kidney Function Estimate | Federico Calò
Estimate glomerular filtration rate (eGFR) using the CKD-EPI 2021 equation and stage CKD according to KDIGO 2022 guidelines. Calculate in browser - no data sent to server.
The eGFR (estimated Glomerular Filtration Rate, estimated glomerular filtration rate) is the main parameter for assessing renal function and classifying chronic kidney disease (CKD). The National Kidney Foundation (NKF) and the American Society of Nephrology (ASN) updated the CKD-EPI equation in 2021, removing the racial correction factor present in the 2009 version: the new formula - published in New England Journal of Medicine (Inker et al., 2021) - uses only serum creatinine, age, and biological sex.
The formula: eGFR = 142 × min(Scr/κ, 1)α × max(Scr/κ, 1)−1.200 × 0.9938Age × [1.012 if female], with κ = 0.7 (F) / 0.9 (M) and α = −0.241 (F) / −0.302 (M). The result is expressed in mL/min/1.73m².
The CKD stage is assigned according to the KDIGO 2022 classification: G1 (≥90), G2 (60–89), G3a (45–59), G3b (30–44), G4 (15–29), G5 (<15 mL/min/1.73m²). At least two pathological values spaced 3 months apart are required for MRC diagnosis.
Source: Inker LA et al. N Engl J Med 2021;385:1737-1749 (DOI 10.1056/NEJMoa2102953). Staging: KDIGO 2022 CKD Guidelines, Kidney Int 2022;103(3 Suppl):S1-S142.
Configure
Result
No results
Enter values and press the button to calculate.
Calculation example
Patient type: Female, 55 years old, serum creatinine 0.9 mg/dL.
- k = 0.7 (female), α = −0.241
- ratio = 0.9 / 0.7 = 1.286 → branch max(ratio, 1)
- maximum term is approximately equal to
- Age term is approximately equal to .
- eGFR ≈ 142 × 1.000 × 0.762 × 0.709 × 1.012 ≈ 77.6 mL/min/1.73m² → Stage G2
[Constants are assumed from Inker 2021 paper - to be verified against Table 1 of the original paper.]
Glossary
- Estimated Glomerular Filtration Rate
- Estimated Glomerular Filtration Rate - estimated kidney filtration rate, expressed in mL/min/1.73m². Measures the kidneys' ability to filter blood per minute.
- Myocardial Risk Classification / Chronic Kidney Disease
- Chronic Kidney Disease (CKD) - persistent reduction in kidney function for at least 3 months. eGFR is the main parameter for KDIGO 2022 classification (G1–G5).
- Serum creatinine (Scr)
- Muscle metabolism waste product, eliminated by renal filtration. Elevated value indicates reduced filtering capacity. Expressed in mg/dL (conversion: 1 mg/dL = 88.4 µmol/L).
- Kidney Disease: Glomerular Filtration Rate (GFR) Classification
- Kidney Disease: Improving Global Outcomes - international organization publishing reference guidelines for kidney diseases. The CKD G1–G5 classification was updated in 2022.
Frequently Asked Questions
What is eGFR CKD-EPI 2021?
The eGFR (estimated Glomerular Filtration Rate) estimates kidney filtration rate to assess renal function. The CKD-EPI 2021 equation (Inker et al., NEJM 2021) is the race-free version approved by NKF and ASN, removing the racial coefficient from the 2009 version.
What is the difference between CKD-EPI 2021 and CKD-EPI 2009?
Version 2009 (Levey et al.) included a correction factor for black patients. Version 2021, developed by the NKF-ASN task force, eliminates this factor entirely: the equation uses only serum creatinine, age, and biological sex. This tool implements only version 2021 race-free.
What does CKD mean and how is it interpreted?
Classification by KDIGO 2022 divides chronic kidney disease (CKD) into 5 stages based on eGFR: G1 (≥90 mL/min/1.73m², normal/elevated), G2 (60–89, mildly reduced), G3a (45–59, mild-moderate), G3b (30–44, moderate-severe), G4 (15–29, severely reduced), G5 (<15, renal insufficiency). Diagnosis of CKD requires at least 2 spaced-out measurements over 3 months.
Are your data secure?
Yes. All calculations occur locally in your browser using the CKD-EPI 2021 equation. No clinical data is transmitted to external servers, AI, or third parties. The tool does not store or process personal data.
Can I use this calculator for diagnosis or treatment decisions?
No. This tool is exclusively informative and NOT a medical device. The calculated eGFR does not replace the nephrologist's clinical evaluation, which considers additional factors (albuminuria, imaging, history, toxic nephrotic drugs). Always consult your doctor for result interpretation.
What creatinine and age values can I enter?
Age between 18 and 120 years, serum creatinine levels between 0.1 and 30 mg/dL. Enter the measured serum creatinine level in mg/dL (not mmol/L). If your lab report shows µmol/L, divide by 88.4 to convert to mg/dL.
How is it used?
- Enter clinical data
Select biological sex, enter age in years and serum creatinine in mg/dL. The calculator uses the CKD-EPI 2021 race-free equation (Inker, NEJM 2021).
- Start calculation
Press "Calculate eGFR". The result is processed in your browser - no data is sent to external servers.
- Interpret eGFR and CKD Stage
The tool shows the estimated eGFR (mL/min/1.73m²) and the CKD stage according to KDIGO 2022 classification (G1–G5). Share the result with your nephrologist for a complete clinical assessment.
- Repeat in time
eGFR should be monitored over time. A single value is not enough for MRC diagnosis - at least 2 values spaced 3 months apart are needed according to the 2022 KDIGO guidelines.
Do you need a custom analysis?
This tool is free and informative. For in-depth analysis with AI on-prem - private data, zero cloud - contact Federico.