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Gestation Network


Centile Calculator

Our Centile Calculators produce customised birthweight centiles using the principles of the GROW (Gestation Related Optimal Weight) method. Through inputting maternal height
and weight, ethnicity, parity, fetal weight, sex and gestation, the applications return a customized birthweight centile. See References and Related Literature for further information.

The calculators are continually being updated, according to availability of new databases from different populations from which additional ethnic coefficients can be derived.
The latest releases contain over 100 Ethnic/Country of Origin and Regional coefficients, and are available as a global version or one specifically for UK populations. For further information, please click here.

The software is provided for free and comes in one of two formats, according to requirement:

  • Individual centile calculator (ICC) - current version (released: 30.4.2020): for day to day practice, to calculate birthweight or estimated fetal weight centiles one at the time.
  • Bulk centile calculator (BCC) - current version (released: 29.9.2022) - an on-line spreadsheet which allows import of large databases to derive fetal or birthweight centiles for audit or research.

To receive either application, please complete the on-line request form, providing

  1. Name, affiliation, and a brief note about the intended use - clinical, audit, or research (specify area).
  2. Type of calculator required (individual or bulk).


GROW software makes calculations on the basis of published principles and formulae, and is released only after rigorous testing for quality assurance.
However Gestation Network or the Perinatal Institute cannot accept responsibility for clinical diagnoses or decisions made on the basis of the software. For more information, see our terms and conditions of use.


© Gestation Network Ltd 2024