About
Adam Reynolds made this calculator. He's a paediatrics specialist registrar from Ireland. As a doctor working with preterm babies, he often needs to calculate and plot growth centiles for the purposes of audit, research, presentations and clinical practice. A handful of other free centile calculators are available, but they are either obsolete or have an inadequate list of features. Some only cover the period up to and shortly after term. Others do not calculate serial measurements simultaneously or store measurements from multiple babies. A few do not provide standard deviation scores. Most do not produce growth charts.
The calculator was originally made for personal use, but published in the hope that either a parent, dietician or other paediatrician will find it useful. If you notice any bugs or would like any additional features, feel free to let Adam know. He might not do anything about it.
References & Acknowledgements
The workbook calculates standard deviation scores and thus centiles using the LMS method. (1) The LMS values are from datasets collected and described by Cole et al. and Fenton et al. (2,3) The centile values produced may in certain cases vary slightly from those produced by other calculators. This is due to differences in interpolation methods and the number of decimal places used in various calculations. The differences between this calculator and the LMSGrowth Excel Add-in for any of the major centile lines are; Length: mean: 0.007cm, max: 0.026cm, Weight: mean: 1.4g, max: 13.6g, OFC: mean: 0.001cm, max: 0.023cm. For values around the median at the lower limits of the UK-WHO growth standard, this results in discrepancies of up to two centiles. The logo was drawn by Brian Fortune. The website charts are created using Chart.js. Initial support for the project was provided by Ruth Carey and Anna Claire Glynn.
- Cole TJ, Green PJ. Smoothing reference centile curves: the LMS method and penalized likelihood. Stat Med. 1992;11(10):1305-19.
- Cole TJ, Williams AF, Wright CM, Group RGCE. Revised birth centiles for weight, length and head circumference in the UK-WHO growth charts. Ann Hum Biol. 2011;38(1):7-11.
- Fenton, Tanis R & Kim, Jae H. A systematic review and meta-analysis to revise the Fenton growth chart for preterm infants. BMC Pediatrics.2013, 13:59
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