eGFR Calculator (CKD-EPI 2021)

Kidney function from creatinine, age and sex with CKD stage. Free, private and instant.

How to use the eGFR Calculator

Choose sex: Male or Female.
Enter age.
Choose creatinine unit on your lab report: mg/dL (US) or µmol/L (UK, EU, Asia).
Answer any extra questions that appear for your choices.
Press Calculate to get an instant result with a colour scale, chart and plain-English explanation.

About the eGFR Calculator

Estimated glomerular filtration rate (eGFR) shows how well your kidneys filter blood. It is calculated from a serum creatinine blood test, your age and your sex. This calculator uses the CKD-EPI 2021 creatinine equation, the race-free equation recommended by the US National Kidney Foundation and the American Society of Nephrology, and places the result in the KDIGO GFR categories G1 to G5. It accepts creatinine in mg/dL (used in the US) or µmol/L (used in the UK, Europe, Australia and most of Asia).

Also known as: CKD-EPI calculator, kidney function calculator, GFR calculator, creatinine to eGFR, CKD stage calculator.

Worked example

Sex: Male
Age: 30 years
Creatinine unit on your lab report: mg/dL (US)
Serum creatinine: 0.9 mg/dL

Estimated GFR (CKD-EPI 2021): 118 mL/min/1.73 m² (G1 - Normal or high). Your estimated glomerular filtration rate is 118 mL/min/1.73 m², KDIGO category G1. Kidney filtering is in the normal or mildly decreased range. CKD is only diagnosed at this level if there are other signs such as protein in the urine.

eGFR: 118 mL/min/1.73 m²
KDIGO category: G1
Creatinine: 0.90 mg/dL · 80 µmol/L
Equation: CKD-EPI 2021 (race-free)

Formula and cut-offs

eGFR = 142 x min(Scr/k, 1)^a x max(Scr/k, 1)^-1.200 x 0.9938^age x 1.012 (if female), where Scr is serum creatinine in mg/dL, k = 0.7 (female) or 0.9 (male) and a = -0.241 (female) or -0.302 (male). µmol/L is converted by dividing by 88.4. KDIGO categories in mL/min/1.73 m²: G1 90 or above, G2 60-89, G3a 45-59, G3b 30-44, G4 15-29, G5 below 15.

Frequently asked questions

What is a normal eGFR?

An eGFR of 90 mL/min/1.73 m² or higher is normal for most adults. Values of 60 to 89 are mildly decreased and common in older adults; they count as chronic kidney disease only if there is other evidence of kidney damage, such as protein in the urine.

What eGFR means chronic kidney disease?

An eGFR below 60 mL/min/1.73 m² for at least 3 months meets the KDIGO definition of chronic kidney disease. Stage G3a is 45-59, G3b is 30-44, G4 is 15-29 and G5, kidney failure, is below 15.

Why was race removed from the eGFR equation?

The 2021 CKD-EPI equation was refitted without a race coefficient. The older 2009 equation added about 16% for Black patients, which could delay diagnosis and specialist referral.

Does eGFR affect my medicine doses?

Yes. Many medicines, including metformin, some antibiotics, anticoagulants and NSAID painkillers, need a lower dose or must be avoided when eGFR is low. Your doctor or pharmacist makes that decision using your lab results.

What is the estimated GFR (CKD-EPI 2021) for a 30-year-old man and a serum creatinine of 0.9 mg/dL?

Estimated GFR (CKD-EPI 2021): 118 mL/min/1.73 m² (G1 - Normal or high). Your estimated glomerular filtration rate is 118 mL/min/1.73 m², KDIGO category G1. Kidney filtering is in the normal or mildly decreased range. CKD is only diagnosed at this level if there are other signs such as protein in the urine. Enter your own numbers above for a personal result.

Sources and references

Written and checked by the MediHub editorial team against the sources above. Read how we build and review our calculators.

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Last updated 2026-10-25. This calculator is for education only and is not medical advice. See the medical disclaimer.