GFR Calculator
Estimate your kidney function (Glomerular Filtration Rate, GFR) from serum creatinine, age and sex using the CKD-EPI 2021 equation.
CKD-EPI 2021 equation (race-free). For clinical use only alongside physician assessment.
How to use the GFR Calculator
- Enter your inputs into the GFR Calculator above.
- Results update instantly as you type — no submit button needed.
- Adjust any value to see how the result changes in real time.
The CKD-EPI 2021 equation
eGFR = 142 × min(SCr/κ, 1)^α × max(SCr/κ, 1)^−1.200 × 0.9938^Age × 1.012 (if female)
SCr is serum creatinine in mg/dL. κ and α are sex-specific constants. The result is mL/min/1.73 m². The 2021 version removed the historical race coefficient.
Worked example
A 50-year-old woman with serum creatinine 0.9 mg/dL: eGFR ≈ 76 mL/min/1.73 m². Same value in a 70-year-old: eGFR ≈ 65. Below 60 sustained is the threshold for chronic kidney disease (CKD).
Frequently asked questions
What is a normal GFR?
Above 90 mL/min/1.73 m² is normal in young adults. GFR declines with age — averaging about 1 mL/min/1.73 m² per year after 40. Below 60 sustained for 3+ months defines CKD.
What causes low GFR?
Diabetes, hypertension, certain medications, autoimmune diseases (lupus, IgA nephropathy) and aging. Dehydration and intense exercise can transiently lower it.
Does this replace lab tests?
No — clinical GFR estimation requires a recent serum creatinine value from a lab. The calculator is a tool for understanding your reported values, not a substitute for medical advice.