Calculate estimated glomerular filtration rate (eGFR) using the CKD-EPI 2021 equation for adults or the Bedside Schwartz equation for children. Get an estimated kidney function result in mL/min/1.73 m² with GFR category guidance.
What Is eGFR?
eGFR (estimated glomerular filtration rate) is an estimate of how well the kidneys are filtering waste from the blood. It is commonly reported as mL/min/1.73 m², a standardized unit that adjusts kidney filtration for a body surface area of 1.73 square meters.
An eGFR value is usually estimated from information such as serum creatinine, age and sex in adults. For children, height is also an important part of the calculation.
eGFR is useful for assessing kidney function and helping healthcare professionals evaluate and monitor chronic kidney disease (CKD). However, eGFR is an estimate rather than a direct measurement of GFR and should always be interpreted together with the patient's medical history, other laboratory results and clinical findings.
How Does the Medinzo eGFR Calculator Work?
The Medinzo eGFR Calculator provides separate calculations for adults and children because kidney-function equations differ between these age groups.
For adults aged 18 years or older, the calculator uses the 2021 CKD-EPI creatinine equation.
For children aged 1–17 years, the calculator uses the Bedside Schwartz equation.
You can enter serum creatinine in either mg/dL or µmol/L. When µmol/L is selected, the calculator converts the value to mg/dL before applying the appropriate equation.
The calculator then displays an estimated GFR rounded to the nearest whole number and shows the corresponding GFR category.
Adult eGFR Formula: CKD-EPI 2021
For adults, this calculator uses the 2021 CKD-EPI creatinine equation developed from a large dataset and designed without the use of a race coefficient.
The adult equation is:
eGFR = 142 × min(Scr/κ, 1)α × max(Scr/κ, 1)−1.200 × 0.9938Age × 1.012 (if female)
Where:
- Scr = serum creatinine in mg/dL
- Age = age in years
- κ = 0.7 for females and 0.9 for males
- α = −0.241 for females and −0.302 for males
The equation produces an estimated GFR in mL/min/1.73 m².
The CKD-EPI 2021 creatinine equation is described by Inker et al. in the New England Journal of Medicine.
Pediatric eGFR Formula: Bedside Schwartz
Children require a different approach because kidney function changes with growth and body size.
For children aged 1–17 years, the calculator uses the Bedside Schwartz equation:
eGFR = 0.413 × Height (cm) ÷ Serum Creatinine (mg/dL)
Where:
- Height = child's height in centimeters
- Serum creatinine = creatinine concentration in mg/dL
- 0.413 = coefficient used in the Bedside Schwartz equation
Because height is part of the equation, an accurate height measurement is important when estimating eGFR in children.
This calculator is intended for children aged 1–17 years. Infants younger than 1 year require age-appropriate clinical assessment and should be evaluated by a qualified pediatric healthcare professional.
Creatinine Unit Conversion
Serum creatinine may be reported in different units depending on the laboratory or country.
The calculator accepts:
- mg/dL
- µmol/L
The conversion used is:
Creatinine (mg/dL) = Creatinine (µmol/L) ÷ 88.4
For example, a creatinine value of 88.4 µmol/L corresponds to approximately 1.0 mg/dL.
Always check the unit reported by your laboratory before entering a creatinine value into an eGFR calculator.
Understanding Your eGFR Result
eGFR results are commonly interpreted using GFR categories. The categories below are used in chronic kidney disease classification:
| GFR Category | eGFR | Description |
|---|---|---|
| G1 | ≥90 | Normal or high |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mildly to moderately decreased |
| G3b | 30–44 | Moderately to severely decreased |
| G4 | 15–29 | Severely decreased |
| G5 | <15 | Kidney failure |
These categories are useful for clinical assessment, but an eGFR number should not be interpreted by itself.
For example, an eGFR of 75 does not automatically mean that a person has chronic kidney disease. CKD assessment also considers whether abnormalities are persistent over time and whether there are other markers of kidney damage, such as albumin in the urine.
eGFR and Albuminuria
Kidney disease assessment commonly considers both GFR and albuminuria.
A urine test called the urine albumin-to-creatinine ratio (UACR) can help detect albumin in the urine. Increased urinary albumin can be an important marker of kidney damage.
This means that two people with a similar eGFR may have different overall kidney-risk profiles depending on their urine albumin level and other clinical findings.
For this reason, an eGFR calculator should be considered a useful estimation tool rather than a standalone diagnostic test.
Example: Adult eGFR Calculation
Consider an adult with the following values:
- Age: 50 years
- Sex: Male
- Serum creatinine: 1.0 mg/dL
The CKD-EPI 2021 equation uses the patient's age, sex and serum creatinine to estimate kidney filtration.
The calculator performs the mathematical steps automatically and reports the estimated result in mL/min/1.73 m².
This example demonstrates how the calculator works. It should not be used to determine whether a particular patient has kidney disease without clinical evaluation.
Example: Pediatric eGFR Calculation
For example, consider a child with:
- Age: 10 years
- Height: 135 cm
- Serum creatinine: 0.7 mg/dL
The Bedside Schwartz equation uses height and serum creatinine:
eGFR = 0.413 × Height ÷ Creatinine
The calculator performs this calculation automatically and reports the estimated result in mL/min/1.73 m².
What Can Affect Serum Creatinine?
Serum creatinine is an important input for creatinine-based eGFR equations, but creatinine concentration can be influenced by factors other than kidney filtration.
These may include:
- Muscle mass
- Dietary intake, particularly recent meat intake
- Age
- Body size
- Certain medicines
- Changes in hydration or illness
- Some medical conditions
People with unusually high or low muscle mass may therefore have an eGFR estimate that does not perfectly represent their actual filtration level.
This is one reason healthcare professionals interpret eGFR together with other clinical information rather than relying on a single number.
eGFR vs GFR
GFR refers to glomerular filtration rate, which describes how much blood plasma is filtered through the kidney glomeruli over a period of time.
eGFR means estimated GFR. It is calculated using an equation rather than directly measuring filtration.
Direct or measured GFR testing can involve specialized methods and is not routinely required for every patient. In everyday clinical practice, estimating GFR from blood-test information is commonly used to assess kidney function.
Because eGFR is an estimate, changes should be interpreted in the context of the patient's overall health and, when appropriate, repeated laboratory testing.
eGFR Calculator Limitations
Although eGFR equations are useful, they have limitations.
- eGFR is an estimate rather than a directly measured GFR.
- Creatinine-based equations can be affected by differences in muscle mass and other factors.
- Results may be less reliable during rapidly changing kidney function.
- A single eGFR value does not by itself establish chronic kidney disease.
- Pediatric and adult equations are not interchangeable.
- Different equations may produce different estimates in some patients.
- Very unusual body composition or clinical circumstances may require additional assessment.
For patients with complex kidney disease or results that do not fit the clinical picture, a healthcare professional may consider additional laboratory tests or other methods of assessing kidney function.
When Should You Talk to a Doctor?
You should discuss your kidney-function results with a healthcare professional if you have an abnormal eGFR, persistent changes in kidney function or other findings suggesting kidney disease.
Medical evaluation is particularly important if an abnormal eGFR occurs together with:
- Protein or albumin in the urine
- Blood in the urine
- High blood pressure
- Diabetes
- Swelling of the legs or feet
- Reduced urine output
- Persistent fatigue or weakness
- Known kidney disease
- A history of kidney stones
Seek prompt medical care for severe symptoms such as markedly reduced urine output, severe swelling, shortness of breath, confusion or other symptoms that may indicate a serious medical problem.
eGFR Calculator for Adults vs Children
Adults and children should not automatically be evaluated using the same eGFR equation.
| Feature | Adults | Children |
|---|---|---|
| Age range in this calculator | 18–100 years | 1–17 years |
| Equation | CKD-EPI 2021 | Bedside Schwartz |
| Main inputs | Age, sex, creatinine | Age, height, creatinine |
| Creatinine unit | mg/dL or µmol/L | mg/dL or µmol/L |
| Result unit | mL/min/1.73 m² | mL/min/1.73 m² |
For infants younger than 1 year, this calculator should not be used as a substitute for an age-appropriate pediatric assessment.
Why Is eGFR Important?
eGFR can help healthcare professionals estimate kidney filtration and monitor kidney function over time.
It can be useful in the assessment and monitoring of chronic kidney disease, medication-related kidney considerations and other situations where kidney function needs to be evaluated.
However, kidney health involves more than one laboratory number. Blood pressure, urine albumin, other blood tests, medical history, imaging and symptoms may all contribute to a complete assessment.
Clinical Notes
eGFR results should be interpreted according to the patient's clinical situation.
A reduced eGFR may be temporary in some situations, while persistent reduction over time may be more clinically significant. Acute illness and rapidly changing kidney function can also affect the usefulness of creatinine-based estimates.
Healthcare professionals may therefore compare results over time instead of relying on a single measurement.
When kidney function is being monitored, trends in eGFR together with urine albumin measurements can provide more useful information than an isolated result.
Frequently Asked Questions
What is an eGFR calculator?
An eGFR calculator estimates kidney filtration using variables such as serum creatinine and age. Adult equations may also use sex, while pediatric equations may use height.
What does eGFR stand for?
eGFR stands for estimated glomerular filtration rate. It is an estimate of how efficiently the kidneys filter blood.
What is a normal eGFR?
An eGFR of 90 or higher is categorized as G1, described as normal or high. However, an eGFR of 90 or higher does not by itself prove that the kidneys are completely normal, because other markers of kidney damage and the patient's clinical situation also matter.
What does an eGFR below 60 mean?
An eGFR between 30 and 59 falls within the G3 category and may indicate decreased kidney function. Chronic kidney disease assessment requires consideration of persistence over time and other evidence of kidney damage.
What does an eGFR below 15 mean?
An eGFR below 15 falls within the G5 category, which is classified as kidney failure. Such a result requires medical evaluation and should not be interpreted by an online calculator alone.
What creatinine level is used for eGFR?
The calculator uses serum creatinine reported in either mg/dL or µmol/L. If µmol/L is selected, the calculator converts the value to mg/dL before applying the equation.
Can I use the adult eGFR equation for a child?
No. This calculator uses the CKD-EPI 2021 equation for adults and the Bedside Schwartz equation for children aged 1–17 years.
Can eGFR diagnose kidney disease?
eGFR is an important part of kidney-function assessment, but one eGFR result alone does not diagnose chronic kidney disease. Healthcare professionals also consider persistence, urine albumin and other evidence of kidney damage.
Does a low eGFR always mean kidney disease?
Not necessarily. The meaning of a low eGFR depends on the value, whether it persists, the patient's age and health, and other laboratory and clinical findings.
Can eGFR change from one test to another?
Yes. Creatinine levels and kidney function can change, and laboratory measurements may vary. Healthcare professionals often consider trends over time when interpreting kidney-function results.
What is the CKD-EPI 2021 equation?
The CKD-EPI 2021 equation is a creatinine-based equation used to estimate GFR in adults. The equation does not use a race coefficient.
What is the Bedside Schwartz equation?
The Bedside Schwartz equation is a pediatric creatinine-based equation that estimates GFR using a child's height and serum creatinine.
What is the unit of eGFR?
eGFR is commonly reported as mL/min/1.73 m².
Can I use this calculator instead of seeing a doctor?
No. The calculator is an educational estimation tool. It cannot replace professional medical assessment, diagnosis or treatment.
Evidence & References
-
Inker LA, Eneanya ND, Coresh J, et al. New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race. New England Journal of Medicine. 2021;385:1737–1749.
View the CKD-EPI 2021 study -
Schwartz GJ, Muñoz A, Schneider MF, et al. New Equations to Estimate GFR in Children with CKD. Journal of the American Society of Nephrology. 2009;20(3):629–637.
View the pediatric eGFR study -
Kidney Disease: Improving Global Outcomes (KDIGO). KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease.
View the KDIGO 2024 CKD Guideline
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Medical Disclaimer
This eGFR calculator is provided for general educational and informational purposes only. It is not intended to replace professional medical advice, diagnosis or treatment.
eGFR is an estimated value and may not accurately represent measured kidney filtration in every individual. Results should be interpreted by a qualified healthcare professional together with the patient's medical history, laboratory results, symptoms and other clinical findings.
Do not make medication, treatment or other healthcare decisions based solely on the result of this calculator.
Last Reviewed: September 2026
Last Updated: September 2026