eGFR Calculator

Fast kidney function estimates using 18 validated adult and pediatric equations.

Enter age, sex, and serum creatinine. Add cystatin C, height, or weight when available to calculate additional equations.

18 validated equationsCKD stage guidanceReference details includedFree forever, without ads

Patient data

Age, sex and one biomarker are enough. Everything else is optional and adds more equations.

RequiredEnter serum creatinine, cystatin C, or both.

Typical 0.7–1.3 mg/dL

Typical 0.5–1 mg/L

OptionalHeight and weight enable the pediatric and Cockcroft-Gault equations plus absolute GFR. UACR adds KDIGO risk staging.

Typical 50–100 kg

Typical 0–30 mg/g

Legacy input — affects CKD-EPI 2009 and MDRD only.

CKD stage reference

G1 (>= 90)
Normal or high
G2 (60-89)
Mildly decreased
G3a (45-59)
Mild to moderate decrease
G3b (30-44)
Moderate to severe decrease
G4 (15-29)
Severely decreased
G5 (< 15)
Kidney failure

FAQ

Which equation should I use?

For most adults, start with CKD-EPI 2021. For children, use pediatric equations such as Schwartz or CKiD. If cystatin C is available, combined equations can improve confidence.

What is a normal eGFR?

In adults, eGFR 90 mL/min/1.73 m2 or higher is typically considered normal. Lower values should be interpreted with albuminuria, trend over time, and clinical context.

Why are there multiple results?

Different equations are validated for different ages, biomarkers, and use cases. The calculator ranks the most appropriate option first and still lets you compare alternatives.

When do height and weight matter?

Weight is needed for Cockcroft-Gault. Height is often important for pediatric equations and for body surface area based conversions.

Can I rely on this alone for clinical decisions?

No. eGFR is an estimate. Use it alongside the patient history, medications, laboratory context, and clinical judgment.