GFR Calculator: eGFR by CKD-EPI 2021 and Schwartz
Estimate kidney function from serum creatinine in mg/dL or µmol/L with the race-free CKD-EPI 2021 equation for adults or the bedside Schwartz equation for children, and see the KDIGO G1 to G5 category. Nothing is uploaded.
Enter a serum creatinine value to estimate the GFR.
About the GFR Calculator
The GFR Calculator estimates your glomerular filtration rate (eGFR), the standard measure of how well the kidneys filter blood, from a serum creatinine result. For adults it uses the CKD-EPI 2021 creatinine equation, which does not use race. For children it uses the bedside Schwartz equation. It also shows the KDIGO GFR category, from G1 (normal or high) to G5 (kidney failure).
Creatinine can be entered in milligrams per decilitre (mg/dL, used in the United States) or micromoles per litre (µmol/L, used in the UK, Europe and Australia). A child's height can be entered in centimetres or in feet and inches.
This is an estimate, not medical advice. Chronic kidney disease is diagnosed by a doctor from repeated tests over at least three months, usually with a urine test for protein, so one result does not mean you have or do not have kidney disease. Creatinine also depends on muscle mass, diet and some medicines. Please discuss your results with your doctor.
How to estimate GFR
Adults
- Choose Adult (18 or over), then Female or Male.
- Enter your age in years.
- Choose the creatinine unit printed on your lab report and enter the value.
Children
- Choose Child (under 18).
- Enter the child's height in centimetres or in feet and inches.
- Enter the creatinine value. The Schwartz equation was developed with creatinine measured by the modern enzymatic method.
The equations
The CKD-EPI 2021 equation (Inker and colleagues, New England Journal of Medicine, 2021) is:
Here is serum creatinine in mg/dL, κ is 0.7 for women and 0.9 for men, and α is −0.241 for women and −0.302 for men. A value in µmol/L is divided by 88.4 first.
The bedside Schwartz equation (Schwartz and colleagues, Journal of the American Society of Nephrology, 2009) is:
Both give a result in mL/min/1.73 m², rounded to a whole number as laboratories report it.
KDIGO categories
| Category | eGFR | Description | | --- | --- | --- | | G1 | 90 or more | Normal or high | | G2 | 60 to 89 | Mildly decreased | | G3a | 45 to 59 | Mildly to moderately decreased | | G3b | 30 to 44 | Moderately to severely decreased | | G4 | 15 to 29 | Severely decreased | | G5 | under 15 | Kidney failure |
Worked example
A 50-year-old man with a creatinine of 1.0 mg/dL (88.4 µmol/L) has an eGFR of 142 × (1.0 ÷ 0.9)^−1.2 × 0.9938^50 = 92 mL/min/1.73 m², category G1.
Privacy
Every calculation runs in your browser. Nothing is uploaded, and your results never leave your device.
Related tools
Work out an exact age with the Age Calculator, convert a height with the Length Converter, or check your weight for your height with the BMI Calculator.
Sources
- Inker, L. A., et al. (2021). New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race. New England Journal of Medicine, 385, 1737–1749.
- Schwartz, G. J., et al. (2009). New equations to estimate GFR in children with CKD. Journal of the American Society of Nephrology, 20(3), 629–637.
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group (2013). KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney International Supplements, 3(1).
Open-source credits
The calculations are implemented in-house in TypeScript, with no third-party libraries. They follow the published CKD-EPI 2021 creatinine equation, the bedside Schwartz equation and the KDIGO 2012 GFR categories.
Frequently asked questions
What is a normal eGFR?
An eGFR of 90 mL/min/1.73 m² or more is category G1, normal or high. Kidney function falls slowly with age, so values of 60 to 89 (G2) are common in older adults and are not counted as kidney disease unless there are other signs of kidney damage, such as protein in the urine.
Why does the calculator not ask for race?
Older equations multiplied the result for Black patients. In 2021 the CKD-EPI group published a new equation without race, and the US National Kidney Foundation and American Society of Nephrology recommend it. This calculator uses that 2021 equation.
How do I convert creatinine from µmol/L to mg/dL?
Divide the value in µmol/L by 88.4. For example, 88.4 µmol/L is 1.0 mg/dL and 132.6 µmol/L is 1.5 mg/dL. You can enter either unit; the calculator converts it for you.
Which equation is used for children?
For children and teenagers under 18 the calculator uses the bedside Schwartz equation from 2009: 0.413 times height in centimetres, divided by creatinine in mg/dL. It needs the child's height rather than age and sex.
Does one low result mean I have kidney disease?
Not necessarily. Creatinine can rise for a while after hard exercise, a large meat meal, dehydration or some medicines. Chronic kidney disease is diagnosed only when a low eGFR or other kidney damage lasts at least three months. Your doctor will usually repeat the test.