Calculation basis and official references
Reviewed on:
This calculator is not a diagnosis, treatment plan, or prescription. Please consult a qualified clinician about your medical decisions.
Formula basis
Computes the difference between the entered birth weight and a fixed national average (3050g for boys, 2960g for girls).
Calculation method
Compares an entered birth weight with the national average birth weight for the given sex.
Exclusions and checks required
- The average does not distinguish singleton vs. multiple births or gestational age, so it may not apply well to preterm infants.
- The national average is based on annual vital statistics and varies slightly by year (though it was flat from 2010 to 2017).
Example input:：Example: boy born at 3200g
sex- Male
grams- 3200
The difference from the average (+150g) does not indicate the infant's health status.
FAQ
Who is this calculator for? Average Birth Weight
Compares a birth weight with the reference national average by sex.
What values should I enter?
Applies to: Population averages
How should I interpret this estimate?
Compares an entered birth weight with the national average birth weight for the given sex.
How to use
- Enter your input values and press Calculate.
- Review the result and compare it with expected context.
- Computes the difference between the entered birth weight and a fixed national average (3050g for boys, 2960g for girls).