We developed a calculator for the baby’s age (in years/month/days), development stage and the percentile. The percentile shows the weight, height, head circumference and body-mass-index on diagrams compared to other children.
Age and Percentile calculator
The age will also be displayed as a green bar in the diagrams below! To calculate the percentile please fill out the weight (optional).
In the following diagrams you can see the development stages of your baby/child until the second year. If your baby does not achieve these milestones it is better to talk with your pediatrician!
Body
Mind
Percentile
The percentile shows how for example our baby’s weight compares to other infants. It tells us what percentage of babies weigh less and what percentage weigh more. Fore example out of a sample of 100 babies, a percentile value of 40 means that our baby weighs more than 40 babies and less than the other 60 babies. A percentile of 50% represents the average or mean weight.
Weight (in kg or lbs)
*Here you can enter multiple measurements. Please enter dates in the format: “Year-Month-Day”. Separate values for multiple babies by comma: “Date, Weight Baby 1, Weight Baby 2, …” and enter decimal numbers with a period (or enter weights in grams)! The first date is the day of birth. If you empty the input field, the single weight from the first form on top will be displayed!
Height (in cm)
Head Circumference (in cm)
Body-Mass-Index (in kg/m2)
*Will be calculated automatically from the entries of weight and length above.
Frequently asked questions
How to weigh the babies/children?
We weigh our babies using this baby scale:
In the beginning when they were small and when travelling we used a luggage scale. We put a baby in a nest and hang the nest from the scale. We do everything above a bed so if the baby slides out it will fall soft… Or we step on a scale with the baby in our hands and substract our own weight.
Which BMI is ok?
For adults everything over 25 kg/m2 is overweight. For children there is no fixed value.From 1 year on the P90 (overweight) and P97 (obesity) percentiles can be used. Best to use the data from Kromeyer-Hausschild 2001 because the data from KiGGs already reflects the overweight of the children in Germany.
What is the difference between the WHO-, KiGGs- und Kromeyer-Hausschild percentiles?
We use the WHO data to calculate the numeric percentile in the first form on the page. The KiGGS percentile was made for Germany in the years 2003 to 2006. It is the default for the diagrams. Kromeyer-Hausschild 2001 et. al. is older data when children where slimmer.
How to measure the head circumference?
We measure using a paper measuring tape from IKEA at the widest part of the head which is ca. 1 cm above the eyebrows and ears. But many times we just go to the pediatrician!
How to measure the body height?
For children until 2 years the length is measured when they are lying down. From 2 years age the body height is measured while standing. That’s why the WHO data is interrupted at 2 years.
Is the data valid for premature babies?
Many times twins are born premature: Then the percentiles are not accurate, esp. in the beginning. That’s why we provided an input field to enter the number of days the baby is born for example before week 40. (But our babies caught up quickly!)
Diary
You can follow the development of our babies in our diary. And you can find the weight development of our babies here.
At which stage is your baby or child right now? Is it behind or maybe even ahead of schedule? When did it smile for the first time? Post in the comments!
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