Use this free online GFR calculator to estimate your kidney function (eGFR) with the 2021 race-free CKD-EPI creatinine equation, based on your serum creatinine level, age, and gender. This estimate is for general informational purposes only and is not a substitute for professional medical advice — always consult a doctor for a full kidney health assessment.
This is a simplified estimate for educational purposes only and is NOT a substitute for professional medical diagnosis. Kidney function assessment requires a doctor's evaluation of your full clinical picture. Consult a healthcare professional.
How to Use the GFR Calculator
Enter your Serum Creatinine level in mg/dL in the "Serum Creatinine (mg/dL)" field.
Enter your Age in years.
Select your Gender from the dropdown.
Click "Calculate eGFR" to view your estimated GFR value and CKD stage.
How eGFR Is Calculated (CKD-EPI 2021)
Glomerular filtration rate is the volume of blood your kidneys filter each minute. Measuring it directly needs special tests, so labs and doctors estimate it from serum creatinine, a waste product made by muscle that healthy kidneys clear steadily. This calculator uses the 2021 CKD-EPI creatinine equation, which dropped the race coefficient used in older versions:
κ (kappa) is 0.7 for women and 0.9 for men, roughly the typical creatinine level for each sex.
α (alpha) is -0.241 for women and -0.302 for men. It applies only when creatinine is below κ.
The 0.9938^Age term lowers the estimate by about 0.6% for every year of age, reflecting the natural decline of kidney function.
The result is expressed in mL/min/1.73 m², meaning it is scaled to an average adult body surface area of 1.73 m² so that results can be compared between people of different sizes.
Worked Example
A 50-year-old man has a serum creatinine of 1.2 mg/dL. Scr/κ = 1.2 ÷ 0.9 = 1.333. Because this is above 1, the alpha term becomes 1 and the second term is 1.333^-1.2 = 0.708. The age term is 0.9938^50 = 0.733. So eGFR = 142 × 0.708 × 0.733 = 73.7 mL/min/1.73 m², which falls in stage G2 (mildly decreased). A 50-year-old woman with the same creatinine would get a noticeably lower estimate, because a creatinine of 1.2 is further above the typical female level.
The table below shows how eGFR changes with creatinine, age and sex. Values are in mL/min/1.73 m² and match what this calculator returns.
Creatinine (mg/dL)
Man, 40
Woman, 40
Man, 60
Woman, 60
0.6
125.1
116.3
110.5
102.7
0.8
114.7
95.5
101.3
84.3
1.0
97.6
73.0
86.2
64.5
1.2
78.4
58.7
69.2
51.8
1.5
60.0
44.9
53.0
39.6
2.0
42.5
31.8
37.5
28.1
3.0
26.1
19.5
23.1
17.3
Interpreting Your eGFR
A single low reading does not mean you have chronic kidney disease (CKD). Under the internationally used KDIGO definition, CKD is diagnosed when eGFR stays below 60 for more than three months, or when there are signs of kidney damage such as protein (albumin) in the urine for more than three months. Stages G1 and G2 count as CKD only when such damage markers are also present, which is why doctors usually order a urine albumin-to-creatinine ratio (UACR) alongside the blood test.
In India, diabetes and high blood pressure are the most common causes of chronic kidney disease. If you have either condition, a yearly creatinine and urine albumin test is commonly advised so that a falling trend is picked up early, when treatment can slow it down.
When the Estimate Can Be Misleading
Unusual muscle mass: bodybuilders can show a falsely low eGFR, while frail, elderly or very thin people and amputees can show a falsely high one, because creatinine depends on how much muscle you have.
Diet and supplements: a large meal of cooked meat or creatine supplements in the hours before the test can temporarily raise creatinine.
Certain medicines, such as trimethoprim and cimetidine, raise creatinine without actually harming the kidneys.
Rapidly changing kidney function (acute kidney injury), pregnancy, and children under 18. The CKD-EPI equation is designed for adults with stable kidney function; paediatric eGFR uses different formulas.
Wrong units: this calculator expects mg/dL, which is what most Indian labs report. If your report shows µmol/L, divide by 88.4 first (for example, 106 µmol/L ÷ 88.4 = 1.2 mg/dL).
When creatinine-based results are doubtful, doctors may order a cystatin C test, which is less affected by muscle mass. Discuss any abnormal result with your doctor or a nephrologist.
Frequently Asked Questions
This calculator uses the 2021 race-free CKD-EPI creatinine equation, which combines your serum creatinine, age, and gender (using gender-specific kappa and alpha constants) to estimate your glomerular filtration rate (eGFR) in mL/min/1.73 m².
The calculator classifies your eGFR result into CKD stages: G1 (90+, normal), G2 (60-89, mildly decreased), G3a (45-59, moderately decreased), G3b (30-44, moderately to severely decreased), G4 (15-29, severely decreased), and G5 (below 15, kidney failure).
In healthy young adults, eGFR is usually above 90 mL/min/1.73 m². It falls gradually with age, so a value of 70 to 85 in a healthy 70-year-old is common. A value below 60 that persists for three months or more meets the threshold for chronic kidney disease, regardless of age.
No. This eGFR calculator provides a simplified estimate for general educational purposes only. It is not a substitute for professional medical diagnosis — consult a doctor for a full assessment of your kidney health.
Divide the µmol/L value by 88.4 to convert it to mg/dL. For example, 80 µmol/L ÷ 88.4 = 0.90 mg/dL. Entering a µmol/L number directly would give a wildly wrong result.
Some labs still use older equations such as MDRD or the 2009 CKD-EPI version, and some round creatinine before calculating. Small differences of a few points are expected. If the difference is large, check that the units and age entered here match your report.