eGFR Calculator
Estimated glomerular filtration rate by the race-free CKD-EPI 2021 creatinine equation, from serum creatinine in mg/dL or µmol/L, age and sex, with the KDIGO G category and a Cockcroft–Gault creatinine clearance from weight.
Result…
How it's calculated
eGFR = 142 × min(Scr ÷ κ, 1)^α × max(Scr ÷ κ, 1)^−1.200 × 0.9938^age × 1.012 [if female] κ = 0.7 (female) or 0.9 (male) · α = −0.241 (female) or −0.302 (male) · Scr in mg/dL (µmol/L ÷ 88.42) Cockcroft–Gault CrCl = (140 − age) × weight (kg) ÷ (72 × Scr) × 0.85 [if female], mL/min KDIGO: G1 ≥ 90 · G2 60–89 · G3a 45–59 · G3b 30–44 · G4 15–29 · G5 < 15
The glomerular filtration rate is how much blood the kidneys filter each minute. It is hard to measure, so labs estimate it from creatinine, a waste product of muscle, with the CKD-EPI equation; the 2021 version, recommended by the US National Kidney Foundation, leaves race out. The result is scaled to an average body surface of 1.73 m² and sorted into the KDIGO G categories. The older Cockcroft–Gault formula estimates creatinine clearance in mL/min from weight and is shown for comparison; the National Kidney Foundation now recommends the race-free eGFR equations instead of it for medicine decisions in adults.
Your numbers, step by step
About the eGFR calculator
This eGFR calculator estimates the glomerular filtration rate, how much blood the kidneys filter each minute, from a serum creatinine result, age and sex. It uses the 2021 CKD-EPI creatinine equation, the race-free version the US National Kidney Foundation recommends for adults, and accepts creatinine in mg/dL or µmol/L (converted at 88.42). The result, in mL/min/1.73 m², is given the KDIGO G category from G1 to G5. If you add a weight in kilograms or pounds, it also shows the older Cockcroft–Gault creatinine clearance for comparison. Every step of the equation is shown with your numbers, so students and curious patients can see how a lab's figure is built. It is information only: your lab already reports eGFR, and only a doctor can say what it means for you. Do not use it to choose medicine doses.
How to use it
- Pick the “Creatinine unit” that matches your report and enter the “Serum creatinine”.
- Enter the “Age” (18 or over) and choose the “Sex”.
- To add the Cockcroft–Gault result, pick kg or lb and enter the “Weight (optional, for creatinine clearance)”.
- Read the eGFR, the KDIGO category and the clearance, and follow the steps through the equation.
Worked example
A woman aged 62 with a creatinine of 1.1 mg/dL (about 97 µmol/L) and a weight of 68 kg. κ = 0.7, so Scr ÷ κ = 1.5714. Because that is above 1, the max term applies: 1.5714^−1.200 = 0.5814, and 0.9938^62 = 0.68. eGFR = 142 × 0.5814 × 0.68 × 1.012 = 56.81, reported as 57 mL/min/1.73 m², KDIGO category G3a. Cockcroft–Gault: (140 − 62) × 68 ÷ (72 × 1.1) × 0.85 ≈ 56.9 mL/min.
Updated
Questions people ask
How is eGFR calculated from creatinine?
The 2021 CKD-EPI equation is eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 if female, with κ = 0.7 and α = −0.241 for women and κ = 0.9 and α = −0.302 for men. The National Kidney Foundation page on the 2021 equation lists these coefficients.
What do the eGFR stages G1 to G5 mean?
KDIGO groups eGFR as G1 (90 or more), G2 (60–89), G3a (45–59), G3b (30–44), G4 (15–29) and G5 (under 15), in mL/min/1.73 m². G1 and G2 alone do not mean kidney disease unless there are other signs of kidney damage, as the National Kidney Foundation explains.
How do I convert creatinine from µmol/L to mg/dL?
Divide by 88.42. A result of 88 µmol/L is about 1.0 mg/dL, and 150 µmol/L is about 1.70 mg/dL.
What is the difference between eGFR and creatinine clearance?
eGFR estimates the filtration rate scaled to an average body size of 1.73 m². Cockcroft–Gault estimates creatinine clearance in mL/min from weight, and the National Kidney Foundation now recommends the race-free eGFR equations instead of it for medicine decisions in adults.
What is a common mistake when using an eGFR calculator?
Entering a µmol/L result with the unit set to mg/dL, or the other way round. A value of 88 read as mg/dL is far outside the range, so check the unit on the report first.
Can I use this eGFR to diagnose kidney disease or dose medicine?
No. It is an estimate for information. Diagnosis needs repeated tests, urine results and a doctor's judgement, and medicine doses should come from your doctor or pharmacist. For a related body-size measure, see the body surface area calculator.