eGFR calculator (CKD-EPI 2021)
For health professionals
Estimated glomerular filtration rate from serum creatinine, age and sex, using the race-free CKD-EPI 2021 equation. It also shows the CKD-EPI 2009 result, which is what Australian laboratories report.
For health professionals. An estimate for adults with stable kidney function. Not valid in acute kidney injury, pregnancy, or at extremes of muscle mass, diet or body size. CKD needs abnormal results for more than 3 months, plus urine albumin-to-creatinine ratio for staging. Nothing you enter leaves this device.
GFR categories (KDIGO)
- G1 · 90 or moreNormal or high. CKD only if there’s other evidence of kidney damage, such as albuminuria.
- G2 · 60 to 89Mildly decreased. CKD only with other markers of kidney damage.
- G3a · 45 to 59Mildly to moderately decreased
- G3b · 30 to 44Moderately to severely decreased
- G4 · 15 to 29Severely decreased
- G5 · under 15Kidney failure
The equations
- CKD-EPI 2021: eGFR = 142 × min(Scr/κ, 1)α × max(Scr/κ, 1)−1.200 × 0.9938age × 1.012 (if female). Scr in mg/dL; κ = 0.7 (female) or 0.9 (male); α = −0.241 (female) or −0.302 (male).
- CKD-EPI 2009: 141 × min(Scr/κ, 1)α × max(Scr/κ, 1)−1.209 × 0.993age × 1.018 (if female); α = −0.329 (female) or −0.411 (male). Shown here without the race coefficient, as reported in Australia.
- Creatinine in µmol/L is divided by 88.4 to give mg/dL.
- The 2021 equation was developed to remove race from eGFR. In Australian data, it gives higher values than 2009 for many older adults, so fewer would be labelled CKD stage 3. Australian laboratories still report CKD-EPI 2009.
Good to know
- eGFR is indexed to 1.73 m² body surface area. Some medicine doses use creatinine clearance (Cockcroft–Gault) or absolute GFR instead: check the product information.
- Creatinine-based eGFR can mislead with very high or low muscle mass, amputation, high meat intake or creatine supplements, and in acute illness. Cystatin C can help when in doubt.
- Diagnosing and staging CKD needs repeat results over at least 3 months, plus urine albumin-to-creatinine ratio (uACR).
- Consider nephrology referral for eGFR under 30, a sustained fall in eGFR, heavy albuminuria, or other concerns, as local guidance advises.
Common questions
Which eGFR equation do Australian labs use?
Australian pathology laboratories report the CKD-EPI 2009 creatinine equation, without a race coefficient. The 2021 race-free equation is used in the US and gives somewhat higher results in many older adults. This calculator shows both.
What is a normal eGFR?
An eGFR of 90 or more is normal or high (G1), and 60 to 89 is mildly decreased (G2). On their own, these aren’t CKD unless there are other signs of kidney damage, such as albumin in the urine.
What eGFR is stage 3 kidney disease?
Stage G3a is an eGFR of 45 to 59 and G3b is 30 to 44 mL/min/1.73 m², if it stays at that level for more than 3 months.
How do I convert creatinine from mg/dL to µmol/L?
Multiply mg/dL by 88.4 to get µmol/L, or divide µmol/L by 88.4 to get mg/dL. For example, 1.0 mg/dL is 88.4 µmol/L.
Why was race removed from eGFR?
Race is a social, not biological, category, and the old race multiplier could delay diagnosis and care for Black patients. The 2021 CKD-EPI equation estimates GFR from creatinine, age and sex only.
Sources
- Inker LA et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med 2021. CKD-EPI 2021 development and validation
- National Kidney Foundation: CKD-EPI creatinine equation (2021). equation coefficients
- NIDDK: previous eGFR equations (CKD-EPI 2009). 2009 coefficients
- Classification of CKD in older Australian adults: CKD-EPI 2009 and 2021 compared. Med J Aust 2025. Australian labs use CKD-EPI 2009
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD. Kidney Int 2024 (PubMed). GFR categories; CKD needs more than 3 months