GFR Calculator
Estimate glomerular filtration rate with the race-free CKD-EPI creatinine equation (2021). Enter age, sex, and serum creatinine in mg/dL or umol/L. Informational, not a diagnosis of chronic kidney disease.
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How to estimate eGFR
- Enter adult age between 18 and 120.
- Select the sex coefficient the equation should use.
- Choose mg/dL or umol/L, then enter serum creatinine.
- Read eGFR in mL/min/1.73 m2 and the numeric KDIGO category sketch.
- Pair with BSA or BMI only for size context, not for diagnosis. Nothing is uploaded.
Estimated GFR
CKD-EPI creatinine 2021 (race-free)
| Equation | 142 × min(Scr/k,1)^a × max(Scr/k,1)^-1.2 × 0.9938^age × (1.012 if female) |
|---|---|
| kappa (k) | 0.7 female, 0.9 male |
| alpha (a) | -0.241 female, -0.302 male |
| Creatinine units | mg/dL or umol/L (÷88.4) |
| Outputs | eGFR and numeric GFR category sketch |
| Advice | Lab estimate only. Not a CKD diagnosis. |
What eGFR means on this page
Estimated GFR summarizes how quickly the kidneys clear creatinine using a published equation. The 2021 CKD-EPI creatinine form used here does not include a race coefficient. Categories shown are numeric sketches only and omit albuminuria and clinical context.
How CKD-EPI 2021 is applied
Scr is serum creatinine in mg/dL. Female uses k=0.7 and a=-0.241; male uses k=0.9 and a=-0.302. eGFR = 142 × min(Scr/k, 1)^a × max(Scr/k, 1)^-1.2 × 0.9938^age × (1.012 if female). umol/L inputs convert by dividing by 88.4.
Use cases
Recreating a lab report eGFR when you already know creatinine. Teaching the race-free 2021 equation in class. Checking unit conversion from umol/L to mg/dL. Not a substitute for nephrology care or full staging.
Default numbers
Age 50, male, Scr 1.0 mg/dL: ratio Scr/k = 1/0.9 ≈ 1.111, so the max term applies. The page reports eGFR near the mid-80s mL/min/1.73 m2 with a G2 numeric sketch when the result is under 90.
Limits
Cystatin C, muscle mass extremes, pregnancy, and acute kidney injury are not modeled. Category labels without albuminuria are incomplete for CKD staging. Informational only. See the disclaimer. CZNull does not receive lab values.