eGFR (estimated Glomerular Filtration Rate) is a measure of how well the kidneys filter blood. It is expressed in mL/min/1.73m², and a normal value is 90 or above.

What is the difference between CKD-EPI 2021 and earlier formulas?

CKD-EPI 2021 is the latest formula that removes the race variable. The 2024 KDIGO guidelines also recommend CKD-EPI 2021 as the current standard.

Why is cystatin C used?

Cystatin C is less affected by muscle mass than creatinine, allowing for a more accurate GFR estimation. It is especially useful in elderly patients, women, and malnourished individuals with lower muscle mass.

eGFR Calculator (Estimated Glomerular Filtration Rate)

Q: What is the EKFC formula?

EKFC (European Kidney Function Consortium, 2021) is a formula that covers the full age spectrum from 2 to 90 years, resolving discontinuity issues when transitioning from pediatric to adult equations.

Q: How is pediatric eGFR calculated?

The Bedside Schwartz (2009) formula is the most commonly used for children, requiring only height and creatinine. The EKFC formula can also be applied to pediatric patients.

Q: What is the difference between MDRD 186 and 175?

MDRD 186 is the original formula based on non-standardized creatinine assays, while MDRD 175 is the version calibrated for IDMS-standardized assays.

Compare eGFR results for adult and pediatric patients using multiple formulas including CKD-EPI 2021, EKFC, MDRD, Schwartz, and Cockcroft-Gault all at once.

For Reference Only This calculator implements formulas published in peer-reviewed academic journals as a reference tool. The results are general reference values, and actual eGFR values may vary depending on laboratory equipment, reagents, measurement methods, and the patient's clinical condition. Do not use these results as the basis for medical diagnosis or treatment decisions. Always consult your healthcare provider.

Adult (18+)

Pediatric (1-17)

Age (years)

Sex

Serum Creatinine (mg/dL)

* Required

Height (cm) [Required for pediatric]

* Required for the Schwartz formula

Pediatric Type

* Used to determine the k constant in the Original Schwartz formula

Creatinine Assay Method

* Determines which MDRD formula applies: 186 (non-standardized) or 175 (IDMS)

Cystatin C (mg/L) [Optional]

* If provided, cystatin C-based formulas will also be calculated

Weight (kg) [Optional]

* If provided, the Cockcroft-Gault formula will also be calculated

CKD (Chronic Kidney Disease) Staging

Stage	eGFR (mL/min/1.73m²)	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

Formulas Used

1. CKD-EPI 2021 (Creatinine) Recommended

The latest standard formula without race variable (NEJM 2021, Inker et al.). Recommended by 2024 KDIGO guidelines.
142 × (Scr/κ)^α × 0.9938^Age × (1.012 if female)
κ = 0.7 (female), 0.9 (male) / α = -0.241 (female) or -0.302 (male) when Scr ≤ κ; -1.200 when Scr > κ

2. CKD-EPI 2021 (Cystatin C)

Cystatin C-based formula less affected by muscle mass.
133 × (CysC/0.8)^α × 0.9961^Age × (0.932 if female)
α = -0.499 when CysC ≤ 0.8; -1.328 when CysC > 0.8

3. CKD-EPI 2021 (Creatinine + Cystatin C) Highest Accuracy

Combined formula using both markers for the most accurate estimate.
135 × (Scr/κ)^α × (CysC/0.8)^β × 0.9961^Age × (0.963 if female)

4. EKFC (European Kidney Function Consortium, 2021)

Full age spectrum formula covering ages 2 to 90. Resolves discontinuity when transitioning from pediatric to adult equations.
107.3 / (Scr/Q)^α × (0.990^(Age-40) if Age > 40)
α = 0.322 when Scr/Q < 1; 1.132 when Scr/Q ≥ 1
Q = age- and sex-specific median creatinine (adult male 0.90, female 0.70 mg/dL)

5. CKD-EPI 2009 (Creatinine)

Previous standard formula (Ann Intern Med 2009, Levey et al.).
141 × (Scr/κ)^α × 0.993^Age × (1.018 if female)

6. MDRD-IDMS (Constant 175) / MDRD Original (Constant 186)

MDRD 175: For IDMS-standardized creatinine. MDRD 186: For non-standardized (original) assays.
175 (or 186) × Scr^(-1.154) × Age^(-0.203) × (0.742 if female)

7. Cockcroft-Gault

Estimates creatinine clearance (CrCl). Used for drug dosage adjustment.
CrCl = ((140 - Age) × Weight) / (72 × Scr) × (0.85 if female)

8. Bedside Schwartz (2009) Pediatric

Simplified pediatric formula (ages 1-17) from the CKiD study. Based on IDMS-standardized creatinine.
eGFR = 0.413 × Height(cm) / Scr

9. Original Schwartz (1976) Pediatric

Original pediatric formula. The k constant varies by age and sex.
eGFR = k × Height(cm) / Scr
k = 0.33 (preterm infant), 0.45 (term infant), 0.55 (child/adolescent female), 0.70 (adolescent male)

Frequently Asked Questions

Q. What is eGFR?

eGFR (estimated Glomerular Filtration Rate) measures how well the kidneys filter blood. It is expressed in mL/min/1.73m², and a normal value is 90 or above.

Q. Is there a CKD-EPI 2025 version?

The 2024 KDIGO guidelines still recommend CKD-EPI 2021 as the current standard. No separate CKD-EPI 2025 formula has been published. EKFC (2021) is the latest alternative formula covering the full age spectrum.

Q. What is the EKFC formula?

EKFC (European Kidney Function Consortium, 2021) covers the full age spectrum from 2 to 90 years. It normalizes by median creatinine (Q value) to resolve discontinuity issues when transitioning from pediatric to adult equations.

Q. How is pediatric eGFR calculated?

The Bedside Schwartz (2009) formula is the most commonly used for children, calculated simply as eGFR = 0.413 × Height / Scr. The EKFC formula can also be applied to pediatric patients.

Q. What is the difference between MDRD 186 and 175?

MDRD 186 is the original formula based on non-standardized assays, while 175 is the IDMS-standardized calibrated version. Most current laboratories use IDMS, so the 175 formula applies.

Q. Can I use this calculator's results for diagnosis?

This calculator is for reference only and does not replace medical diagnosis. Always consult a qualified healthcare professional for accurate assessment.

Disclaimer
This eGFR calculator is a reference tool based on formulas published in peer-reviewed academic journals. It must not be used as the basis for medical diagnosis, treatment decisions, drug dosage adjustments, or any other clinical judgment.

Calculated results may differ from actual values due to the following factors:

Type and calibration status of laboratory equipment and reagents
Creatinine assay method (IDMS standardization status)
Patient's muscle mass, diet, hydration status, and medications
Acute kidney injury and other situations with rapidly changing kidney function
Special populations such as pregnant women, severely obese patients, and amputees

If accurate kidney function assessment is needed, always consult your healthcare provider and consider measured GFR (e.g., inulin clearance) if necessary.

This calculator is provided as a reference for educational and research purposes.
This tool cannot replace the judgment of a healthcare professional.
The creators assume no liability for any direct or indirect damages arising from the use of this calculator.

References

CKD-EPI 2021 (Creatinine, Cystatin C, Combined)
Inker LA, Eneanya ND, Coresh J, et al. New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race. N Engl J Med. 2021;385(19):1737-1749. doi:10.1056/NEJMoa2102953
CKD-EPI 2009 (Creatinine)
Levey AS, Stevens LA, Schmid CH, et al. A New Equation to Estimate Glomerular Filtration Rate. Ann Intern Med. 2009;150(9):604-612. doi:10.7326/0003-4819-150-9-200905050-00006
EKFC 2021 (Full Age Spectrum)
Pottel H, Björk J, Courbebaisse M, et al. Development and Validation of a Modified Full Age Spectrum Creatinine-Based Equation to Estimate GFR. Ann Intern Med. 2021;174(2):183-191. doi:10.7326/M20-4366
MDRD
Levey AS, Coresh J, Greene T, et al. Using Standardized Serum Creatinine Values in the MDRD Study Equation. Ann Intern Med. 2006;145(4):247-254. (IDMS 175 calibration)
Levey AS, Bosch JP, Lewis JB, et al. A More Accurate Method To Estimate GFR from Serum Creatinine. Ann Intern Med. 1999;130(6):461-470. (Original 186)
Cockcroft-Gault
Cockcroft DW, Gault MH. Prediction of Creatinine Clearance from Serum Creatinine. Nephron. 1976;16(1):31-41. doi:10.1159/000180580
Bedside Schwartz 2009 (Pediatric)
Schwartz GJ, Muñoz A, Schneider MF, et al. New Equations to Estimate GFR in Children with CKD. J Am Soc Nephrol. 2009;20(3):629-637. doi:10.1681/ASN.2008030287
Original Schwartz 1976 (Pediatric)
Schwartz GJ, Haycock GB, Edelmann CM Jr, Spitzer A. A Simple Estimate of Glomerular Filtration Rate in Children Derived from Body Length and Plasma Creatinine. Pediatrics. 1976;58(2):259-263.
KDIGO 2024 Guidelines
KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4S):S117-S314.

The references above are the original publications for each formula. This calculator's implementation is a JavaScript conversion of the formulas published in those papers and is not affiliated with the original authors or journals.