eGFR Calculator

Calculate estimated GFR using the race-free CKD-EPI 2021 equation. Includes MDRD comparison, pediatric Schwartz formula, cystatin C eGFR, and KDIGO CKD staging.

yrs
mg/dL
eGFR (mL/min/1.73m2)
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CKD Stage —
Kidney Function —
Extended More scenarios, charts & detailed breakdown ▾
yrs
mg/dL
eGFR (CKD-EPI 2021)
—
CKD Stage —
Professional Full parameters & maximum detail ▾
yrs
mg/dL
mg/L
eGFR (CKD-EPI Creatinine 2021)
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eGFR (CKD-EPI Cystatin C) —
eGFR (Combined Cr+CysC) —
CKD Stage —
Dialysis Threshold Note —

How to Use This Calculator

  1. Enter your age and serum creatinine (mg/dL) from a blood test.
  2. Select your sex.
  3. Results show eGFR and CKD stage (G1-G5).
  4. Use MDRD tab to compare with the older MDRD equation.
  5. Use Professional for cystatin C-based eGFR and combined estimate.

Formula

eGFR = 142 x min(Cr/k, 1)^a x max(Cr/k, 1)^-1.200 x 0.9938^Age x 1.012 (female)

k = 0.7 (female) or 0.9 (male). CKD-EPI 2021 race-free equation (Inker et al., NEJM 2021).

Example

Example: 55-year-old male, Cr = 1.2 mg/dL. Cr/k = 1.2/0.9 = 1.33 > 1. eGFR = 142 x (1.33)^-1.200 x (0.9938)^55 approx 73.4 mL/min/1.73m2 (Stage G2).

Frequently Asked Questions

  • CKD-EPI 2021 is the current gold-standard equation for estimating GFR from serum creatinine. Updated in 2021 to remove race as a variable. It uses creatinine, age, and sex only.
  • The 2021 NKF/ASN Task Force removed the race variable because race is a social construct, not a biological determinant. The previous African-American multiplier led to under-diagnosis of CKD in Black patients. CKD-EPI 2021 performs equally well across racial groups.
  • True GFR requires inulin clearance (impractical clinically). eGFR uses blood tests only and is normalized to 1.73 m2 BSA for standardization. Creatinine clearance (Cockcroft-Gault) uses weight and is preferred for drug dosing. eGFR is preferred for CKD staging.
  • Cystatin C is a protein filtered by the kidneys that is less affected by muscle mass than creatinine. CKD-EPI cystatin C or the combined creatinine+cystatin C equation is more accurate in elderly, very lean, or very muscular patients.
  • KDIGO guidelines recommend nephrology referral when eGFR < 30 (G4), when eGFR drops >5 mL/min in 1 year, or when CKD is complicated by significant proteinuria, resistant hypertension, or uncertain diagnosis.

Related Calculators

🫘 GFR Calculator (Cockcroft-Gault) 💧 Creatinine Clearance 📐 Body Surface Area ⚖️ BMI Calculator
Sources & References (5) ▾
  1. Inker LA et al. (2021) — New Creatinine and Cystatin C Equations for CKD, NEJM — New England Journal of Medicine
  2. KDIGO 2024 CKD Guidelines — KDIGO
  3. NIDDK — GFR Estimating Equations — NIH / NIDDK
  4. National Kidney Foundation — eGFR Calculator and Staging — National Kidney Foundation
  5. Schwartz GJ & Work DF (2009) — Measurement and Estimation of GFR in Children, CJASN — Clinical Journal of the American Society of Nephrology