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Newborn Bilirubin Calculator

Assess the risk of newborn jaundice using the Bhutani hour-specific bilirubin nomogram — based on postnatal age in hours and total serum bilirubin.

12 – 168 hours (0.5 – 7 days)

Serum or transcutaneous bilirubin value

Enter postnatal age (12 – 168 hours) and total bilirubin to see the risk zone.

How it works

The Bhutani nomogram (Pediatrics 1999) maps a newborn's total serum bilirubin to an hour-specific percentile. Four risk zones are defined by the 40th, 75th, and 95th percentiles of TSB values from healthy term and near-term infants. Applies to infants ≥ 35 weeks gestation and ≥ 2000 g — not to preterm or sick newborns. Treatment thresholds follow the AAP 2022 guideline.

This estimate is not a diagnosis. Treatment decisions (e.g. phototherapy) belong to the pediatrician or neonatologist. Risk factors such as hemolysis, late-preterm birth, or sepsis lower the action thresholds.

Frequently Asked Questions

What is newborn jaundice?+
Newborn jaundice (icterus neonatorum) results from elevated bilirubin in the blood. Mild yellowing of the skin in the first days of life is common and usually harmless — but very high values can damage the brain (kernicterus). Timely risk assessment is therefore important.
How does the Bhutani nomogram work?+
It compares the infant's total serum bilirubin (TSB) to age-specific percentiles derived from a large cohort of healthy term newborns. A value above the 95th percentile indicates a high risk of significant hyperbilirubinemia.
Which babies is this calculator for?+
Term and near-term newborns ≥ 35 weeks gestation and ≥ 2000 g, between 12 and 168 hours of age (0.5 – 7 days). It is not appropriate for preterm or sick infants — they require individualised thresholds.
What are risk factors for severe jaundice?+
Major risk factors include hemolysis (e.g. blood-group incompatibility, G6PD deficiency), lower gestational age (35–36 weeks), feeding difficulties with weight loss, cephalohematoma, a sibling who needed phototherapy, and East Asian ancestry. These lower the treatment thresholds.
When is phototherapy needed?+
Indications follow the AAP 2022 guideline: thresholds depend on postnatal age, gestational age, and risk factors. Only the pediatrician decides — this calculator provides orientation, not a treatment decision.
How is bilirubin measured?+
The gold standard is total serum bilirubin (TSB) from venous or capillary blood. Transcutaneous bilirubinometers (TcB) screen on the skin — values ≥ 14 mg/dL or those close to action thresholds are confirmed by serum measurement.
What does mg/dL ⇄ µmol/L mean?+
Both units describe the same concentration. Conversion factor: 1 mg/dL ≈ 17.1 µmol/L. The calculator converts automatically — enter the unit your laboratory report uses.

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Background

Newborn Jaundice: Bilirubin Risk Made Simple with the Bhutani Nomogram

8 min