Birthweight Percentile Calculator
Result
Birthweight Percentile Calculator Estimate where a baby's birth weight falls on a growth chart. Enter the birth weight along with the reference mean and standard deviation for the baby's gestational age and sex, and this calculator returns the z-score and — free online calculator.
Formula
- Birthweight Percentile Calculator calculates its result from Standard Deviation, Birth Weight, Mean, Phi Z. It uses the formula z = (birth weight − mean) ÷ standard deviation; percentile = Φ(z). Change any input to recalculate the result instantly. This is an informational calculation and is not medical advice.
- The main inputs are Standard Deviation, Birth Weight, Mean, Phi Z. Enter them in the units and format shown in the calculator.
- Use the measurement units shown beside each field. The result is an estimate and should be interpreted in context.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Birthweight Percentile
- Standard Deviation: 2
- Birth Weight: 3
- Mean: 4
- Phi Z: 5
Using Standard Deviation = 2, Birth Weight = 3, Mean = 4, Phi Z = 5, the calculated result is 5.
Sample result: Calculating…
Frequently asked questions
What does the Birthweight Percentile calculate?
Birthweight Percentile Calculator Estimate where a baby's birth weight falls on a growth chart. Enter the birth weight along with the reference mean and standard deviation for the baby's gestational age and sex, and this calculator returns the z-score and — free online calculator.
Which values should I enter?
Enter Standard Deviation, Birth Weight, Mean, Phi Z using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: z = (birth weight − mean) ÷ standard deviation; percentile = Φ(z).
Why might my result differ from another source?
Results can differ because measurement methods, rounding and assumptions vary. This calculator is an estimate and is not a medical diagnosis.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.