Bedside Schwartz Calculator — Pediatric eGFR from Height and Creatinine
Estimate GFR in children and teens with the 2009 bedside Schwartz equation (0.413 × height ÷ serum creatinine), in mg/dL or µmol/L, with the KDIGO GFR category.
How it works
eGFR (mL/min/1.73 m²) = 0.413 × height (cm) ÷ serum creatinine (mg/dL) · creatinine µmol/L ÷ 88.4 = mg/dL. Equivalent SI form: eGFR = 36.5 × height (cm) ÷ creatinine (µmol/L).
The bedside Schwartz equation was derived by Schwartz and colleagues (JASN 2009) in the Chronic Kidney Disease in Children (CKiD) study, using measured iohexol GFR and enzymatic creatinine. It replaced the original 1976 Schwartz formula, whose k constants (0.55 and others) were calibrated to the older Jaffe creatinine method and now overestimate GFR. It is intended for children and adolescents about 1–18 years old; in infants GFR is physiologically lower, and in teenagers near adult size the CKiD U25 or adult equations may be preferred. The KDIGO categories G1–G5 describe kidney function, but CKD also requires markers of kidney damage or a GFR under 60 for more than 3 months.
Worked example
A child 120 cm tall has an enzymatic serum creatinine of 0.5 mg/dL (44 µmol/L): eGFR = 0.413 × 120 ÷ 0.5 = 99 mL/min/1.73 m² — KDIGO category G1, normal or high.
Sources: Schwartz GJ et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol 2009;20:629–637 · KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease
Frequently asked questions
What is the bedside Schwartz formula?
eGFR = 0.413 × height in cm ÷ serum creatinine in mg/dL. With creatinine in µmol/L, use 36.5 × height ÷ creatinine.
Why 0.413 and not 0.55?
The original Schwartz constant 0.55 was calibrated to the older Jaffe creatinine assay. Modern enzymatic, IDMS-traceable assays read lower, so the updated 2009 constant is 0.413. Using 0.55 with today’s creatinine overestimates GFR.
What is a normal GFR in children?
From about age 2, GFR adjusted to 1.73 m² reaches adult values of roughly 90–130 mL/min/1.73 m². Newborns and infants have much lower GFR that matures over the first two years.
Can I use this for adults?
No. For adults use CKD-EPI, which is the standard adult eGFR equation. The bedside Schwartz equation was validated for children and adolescents.
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Clinical decision tool for education and for use by trained clinicians alongside clinical judgement — not a diagnosis and not a substitute for medical assessment. Scores and cut-offs come from the cited validation studies and may not apply to every patient; follow local protocols.