Pediatric GFR Calculator (Schwartz Formula)
Estimate glomerular filtration rate in children with the 2009 bedside Schwartz equation — eGFR = 0.413 × height / serum creatinine — plus the original Schwartz k-values as a legacy option.
Estimate glomerular filtration rate in children with the 2009 bedside Schwartz equation — eGFR = 0.413 × height / serum creatinine — plus the original Schwartz k-values as a legacy option.
Educational estimate only — not medical advice. The bedside formula was validated in children roughly 1–17 years old with steady-state creatinine. It is not for drug dosing, and a single result does not diagnose chronic kidney disease — discuss any result with a pediatrician.
KDIGO groups eGFR into six G categories. Click a row to see what it means. Remember: a G category alone is not a CKD stage — full staging also uses the cause, the albuminuria category (A1–A3), and persistence beyond 3 months.
| Category | eGFR (mL/min/1.73m²) | Term |
|---|---|---|
| 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 |
| Group | k | Notes |
|---|---|---|
| Preterm infant, under 1 year | 0.33 | Brion/Schwartz modification for low muscle mass |
| Full-term infant, under 1 year | 0.45 | Schwartz 1984 infant study |
| Child 1–12 yr / adolescent girl | 0.55 | Original 1976 formula (Pediatrics 58:259–263) |
| Adolescent boy | 0.70 | Higher muscle mass adjustment |
The 2009 bedside Schwartz formula estimates GFR in children as eGFR = 0.413 x height(cm) / serum creatinine(mg/dL), in mL/min/1.73m². It was developed by Schwartz and colleagues (Journal of the American Society of Nephrology, 2009) from the Chronic Kidney Disease in Children (CKiD) study, using serum creatinine measured enzymatically and standardized to IDMS reference material.
No. This tool is for children and uses the Schwartz formula (height and serum creatinine only). Adults should use our adult glomerular filtration rate calculator, which uses the race-free CKD-EPI 2021 equation with age, sex, and serum creatinine. The two formulas were developed for different populations and are not interchangeable.
Use 0.413 (the 2009 bedside constant) with modern laboratory creatinine measurements - it is the default in this calculator and matches IDMS-traceable enzymatic assays. The older constants (0.55 for children, 0.70 for adolescent boys) were calibrated to pre-IDMS Jaffe assays; applying them to today's IDMS-traceable creatinine overestimates GFR by roughly 20-40%, so they are kept here as a legacy option only.
The original Schwartz equation is eGFR = k x height(cm) / serum creatinine(mg/dL), where k is a constant chosen by age group: 0.33 for preterm infants under 1 year, 0.45 for full-term infants under 1 year, 0.55 for children aged 1-12 and adolescent girls, and 0.70 for adolescent boys. Height acts as a stand-in for muscle mass, because creatinine is a breakdown product of muscle and children grow.
Divide the µmol/L value by 88.4. For example, 88.4 µmol/L equals 1.0 mg/dL. This calculator performs the conversion automatically when you select µmol/L as the creatinine unit.
KDIGO groups eGFR into G categories: G1 (90 or above, 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), and G5 (below 15, kidney failure). A G category alone is not a CKD stage - full staging also needs the cause, an albuminuria category, and persistence beyond 3 months.
The 2009 bedside formula was developed and validated in children aged about 1 to 17 years, so results under 1 year should be interpreted with extra caution - creatinine in newborns reflects the mother's creatinine at first. The original Schwartz equation offers infant constants (0.33 for preterm, 0.45 for full-term infants) as a legacy option, but neonatal kidney function is best assessed directly by a pediatrician or pediatric nephrologist.
Creatinine is produced by muscle, and children gain muscle as they grow taller - so the same creatinine value means different kidney function at different heights. Height is used as a practical stand-in for muscle mass, which is why the Schwartz formula works from a simple height-to-creatinine ratio instead of needing age- and sex-specific tables.
In the original development study, about 87.7% of bedside Schwartz estimates fell within 30% of the directly measured GFR, and 45.6% within 10%. That makes it a useful screening and monitoring tool, but it remains an estimate - it does not replace a measured GFR or a clinician's interpretation of the full laboratory picture.
No. This calculator is an educational tool only and is not medical advice. Do not use its result to diagnose kidney disease, adjust medication, or decide on treatment for a child - discuss any result with a pediatrician or pediatric nephrologist, who will interpret it alongside repeat laboratory tests and the child's full history.
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