eGFR Calculator (CKD-EPI 2021)
EGFR calculator using the race-neutral CKD-EPI 2021 equation (Inker et al, NEJM 2021). Estimate kidney function from serum creatinine, age, and sex. Educational use only.
eGFR Calculator
Please tick the acknowledgement above before calculating.
How to use the eGFR calculator
Get your serum creatinine value
Serum creatinine (Scr) is a routine lab on a Comprehensive Metabolic Panel (CMP) or Basic Metabolic Panel (BMP). Your most recent value, in mg/dL (US units) or μmol/L (international — divide by 88.4 to convert to mg/dL). Find it on your patient portal or lab report.
Enter sex at birth + age
Sex at birth (not gender identity) is a required CKD-EPI input — male vs female biology produces different creatinine baselines. Age in years; CKD-EPI is validated for adults 18-110.
Acknowledge the disclaimer
Tick the acknowledgement checkbox. This tool computes an ESTIMATE for educational reference; a clinical diagnosis requires confirmed lab work and physician interpretation in clinical context.
Read the eGFR + KDIGO stage
Result is in mL/min/1.73m². The KDIGO 2024 staging: G1 ≥ 90 (normal), G2 60-89 (mild), G3a 45-59, G3b 30-44, G4 15-29 (severe), G5 <15 (failure). Stages G3 and below typically warrant nephrology follow-up.
Discuss with your physician
eGFR varies day-to-day with hydration, muscle mass, recent protein intake, and lab assay calibration. A single value isn't a diagnosis. Persistent eGFR < 60 for ≥3 months + kidney damage marker (proteinuria, etc.) defines CKD. Bring this calculation to your healthcare provider to interpret in clinical context.
eGFR — the kidney function estimate every adult should understand
The estimated Glomerular Filtration Rate (eGFR) is the most-used measure of kidney function in clinical practice. It estimates how much blood your kidneys filter per minute, normalised to a standard 1.73m² body surface area. The "estimated" qualifier matters: directly measuring GFR requires inulin or iothalamate clearance studies done in research settings. For everyday clinical use, eGFR is calculated from serum creatinine — a routine, cheap lab test — using one of several equations. The current standard is the CKD-EPI 2021 race-neutral equation, published in the New England Journal of Medicine (Inker et al, 2021). It replaced the older 2009 CKD-EPI equation which used a race coefficient that was discontinued after equity concerns about race-based clinical algorithms.
Why race was removed
The 2009 CKD-EPI equation included a race coefficient (1.159× for Black patients) based on observed creatinine differences. This was statistically real but biologically misattributed — Black patients had higher average serum creatinine for reasons related to body composition + diet, not race per se. The NKF-ASN joint task force, convened in 2020 and reporting in 2021 (Delgado et al., Am J Kidney Dis 2022;79(2):268-288), concluded that race-based eGFR contributed to delayed transplant referrals and other clinical disparities and recommended the race-free 2021 equation. The 2021 equation drops race entirely, using only sex + age + creatinine. The trade-off: slight reduction in average accuracy, large reduction in bias. Current US clinical practice has migrated to the race-neutral equation.
eGFR is the single number that determines whether a patient is referred to nephrology, starts accruing kidney-transplant waiting time (OPTN policy: eGFR or creatinine clearance ≤ 20 mL/min, or dialysis), or has medications adjusted for kidney function. Which equation produces it therefore matters — and in 2022 OPTN required the race-neutral one for waiting-time calculations.
KDIGO staging + what each means
The KDIGO (Kidney Disease: Improving Global Outcomes) staging system uses eGFR + albuminuria to classify CKD. eGFR stages: G1 (≥90): normal — but if structural damage or albuminuria is present, still classified as CKD stage 1. G2 (60-89): mildly decreased — often normal aging. G3a (45-59): mild-moderate decrease — nephrology consultation typically warranted. G3b (30-44): moderate-severe. G4 (15-29): severe — preparing for renal replacement therapy. G5 (<15): kidney failure — dialysis or transplant needed. Below G4, focus shifts from prevention to managing complications: anemia (EPO deficiency), bone disease (CKD-MBD), cardiovascular risk, electrolyte derangements.
ASEAN context — CKD prevalence + screening
Chronic kidney disease is common across ASEAN and diabetes is its leading driver everywhere in the region, which is why diabetes clinics in Singapore, Malaysia, Indonesia and Thailand pair an annual eGFR with a urine albumin test. Published prevalence figures differ by survey, age range and definition, so this page does not quote a single percentage for any country — look to the national renal registry (Singapore Renal Registry, Malaysian Dialysis and Transplant Registry) for current numbers. Two practical points travel across borders: most laboratories in the region report creatinine in μmol/L, so convert before using this calculator; and laboratories have moved to the 2021 equation at different times, so check which one was used before comparing values across years.
CKD-EPI 2021 dropped race, and 1.73 m² is the body surface it indexes to
CKD-EPI 2021: the current US standard equation. Race-neutral. Published in NEJM 2021;385:1737.
Normalised to 1.73 m² body surface area. For very large or small adults, indexed eGFR may differ from absolute.
eGFR < 60 for ≥ 3 months plus a kidney damage marker (proteinuria, structural) = CKD diagnosis.
Serum creatinine varies with muscle mass, hydration, recent protein intake, certain medications. A single value is a snapshot.
Cystatin C-based eGFR is more accurate but more expensive. Used when muscle mass is atypical or for confirmation.
The 2021 update removed the race coefficient after equity concerns about race-based clinical algorithms.
KDIGO stages G3a/G3b distinction matters: G3b (30-44) has materially higher mortality + progression risk than G3a (45-59).
Drug dose adjustments: many medications need renal dosing at eGFR < 60. Common: metformin, NSAIDs, antibiotics.
US transplant waiting time starts accruing at eGFR or creatinine clearance ≤ 20 mL/min or at dialysis start (OPTN policy); a candidate can be registered at any eGFR.
Most ASEAN laboratories report creatinine in μmol/L; divide by 88.4 to get the mg/dL this equation expects (88.4 μmol/L = 1.0 mg/dL).
Frequently asked questions
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Single-value variation of 5-10 mL/min/1.73m² is common and often not clinically meaningful. Causes: hydration status, recent protein intake, medications (NSAIDs, certain antibiotics, IV contrast), changes in muscle mass, lab assay differences between machines. Persistent decline over multiple measurements (3+ months) at the same lab is more meaningful than a single value change. Bring trends, not snapshots, to your nephrologist.
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The 2009 equation had a race coefficient that produced higher eGFR values for Black patients given the same creatinine. This was statistically derived but contributed to delayed transplant referrals + nephrology care. The 2021 equation drops race. Inker et al. (NEJM 2021) report that the race-free equation is slightly less accurate on average but far less biased between groups. In practice it gives Black patients a lower eGFR than the 2009 equation did for the same creatinine, and everyone else a slightly higher one — which moves some patients across a stage boundary in each direction. Use the 2021 equation for current US clinical practice, and note which equation a lab used before comparing old and new results.
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No — CKD-EPI is validated for adults 18+. For pediatrics, use the Bedside Schwartz equation: eGFR = 0.413 × height (cm) / serum creatinine (mg/dL). This requires height which adults don't need. Pediatric nephrologists also use cystatin C-based equations for certain indications. This calculator is not validated for <18 years old.
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This calculator uses mg/dL (US units). To convert μmol/L to mg/dL, divide by 88.4. Example: serum creatinine 88 μmol/L = 88/88.4 ≈ 1.0 mg/dL. Most ASEAN countries use μmol/L; US uses mg/dL. Many lab reports show both units. Double-check before entering.
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Kidney function declines gradually with age from roughly the fourth decade onward — the equation encodes this in its 0.9938^age term, about 0.6% per year — so an older adult with a perfectly normal creatinine gets a lower eGFR than a younger one. This is normal aging, not necessarily disease. KDIGO recognises that many older adults have eGFR 60-89 (G2 stage) without "kidney disease" per se. The combination of eGFR + albuminuria (urinary protein) is what distinguishes normal aging from progressive CKD.
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Likely, but eGFR alone doesn't guarantee kidney health. Early CKD (G1) can have normal eGFR but proteinuria or structural abnormalities. Check: urine albumin-to-creatinine ratio (UACR) < 30 mg/g is normal. Renal ultrasound (if indicated) for structural disease. Blood pressure, diabetes control, hydration also matter. eGFR is one of multiple markers — discuss the complete picture with your physician.
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Cockcroft-Gault (1976) is an older creatinine clearance formula still used for some drug dosing. Differs from CKD-EPI: uses body weight (not body surface area), no race factor (always), validated for older populations. For modern CKD classification, KDIGO recommends CKD-EPI 2021. For specific drug dosing (e.g. some antibiotics, anticoagulants), the FDA label may still specify Cockcroft-Gault. When in doubt, use the equation specified by the medication's prescribing information.
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Yes if you have diabetes, hypertension, or family history of CKD. The urine albumin-to-creatinine ratio (UACR) detects early kidney damage before eGFR drops — many patients have normal eGFR but elevated albuminuria, defining stage G1A2 CKD. KDIGO classification uses BOTH eGFR + albuminuria categories. ACR < 30 mg/g = A1 (normal), 30-300 = A2 (moderately increased), > 300 = A3 (severely increased).
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No. Age, sex, creatinine — every input stays in your browser. The CKD-EPI 2021 computation runs entirely as client-side JavaScript. Open DevTools → Network and confirm zero outbound requests. Safe for personal lab-result analysis.
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Primary source: Inker LA, Eneanya ND, Coresh J, et al. New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race. NEJM 2021;385:1737-1749. DOI 10.1056/NEJMoa2102953. KDIGO 2024 CKD Guidelines — kdigo.org. NKF-ASN task force report: Delgado C, Baweja M, Crews DC, et al. A Unifying Approach for GFR Estimation. Am J Kidney Dis 2022;79(2):268-288. UpToDate + Lexicomp have summary tables for drug renal dosing thresholds.
Method & sources
How it computes
CKD-EPI 2021 race-free creatinine equation: eGFR (mL/min/1.73 m²) = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 [if female], with κ = 0.7 (female) / 0.9 (male) and α = −0.241 (female) / −0.302 (male); Scr in mg/dL, age 18–110. The result is banded into KDIGO GFR categories G1 (≥ 90) to G5 (< 15).
What this tool implements
- Inker et al. 2021 CKD-EPI creatinine equation without race (coefficients 142, κ 0.7/0.9, α −0.241/−0.302, −1.200, 0.9938, 1.012).
- KDIGO 2024 GFR categories: G1 ≥ 90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 < 15 mL/min/1.73 m².
- Creatinine accepted in mg/dL; μmol/L ÷ 88.4 conversion stated on the page; adults 18–110 only (paediatric Bedside Schwartz noted but not implemented).
- Educational estimate gated behind a medical acknowledgement with a physician CTA.
Sources
- Inker LA, Eneanya ND, Coresh J, et al. New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race. N Engl J Med 2021;385(19):1737-1749. PMID 34554658. doi:10.1056/NEJMoa2102953
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int 2024;105(4S):S117-S314. doi:10.1016/j.kint.2023.10.018
- Delgado C, Baweja M, Crews DC, et al. A Unifying Approach for GFR Estimation: Recommendations of the NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease. Am J Kidney Dis 2022;79(2):268-288.e1. PMID 34563581.
- Schwartz GJ, Muñoz A, Schneider MF, et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol 2009;20(3):629-637. PMID 19158356 (Bedside Schwartz 0.413 × height/Scr, cited for the paediatric FAQ).
What can make this go out of date
- none at runtime
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