Il ideal weight of children it is not an indication of absolute value: to calculate the ideal weight, in fact, it is always necessary to consider several factors such as age and relationship with height. The growth of a child in his first years of life is very important and closely linked physical activity and healthy eating.
For your baby to be able to grow healthy, it is good to know what your ideal weight should be, to learn how to calculate the body mass index and to know how to read the tables with the growth percentiles. Obviously, to monitor the ideal weight of children - since there are no absolute laws - it is always good to be able to consult with your pediatrician of trust.
So let's try together to understand how to calculate the ideal weight of children, what it should be according to the tables of the World Health Organization and how calculate percentiles of growth.
How is the ideal weight of children calculated?
Let's repeat it one more time: the ideal weight of children it is not a unique and absolute value, but only a general indication. What is generally referred to as an ideal weight or ideal weight for children is more of a range of values which indicate what the normal weight should be at a given age. Don't panic, then, if your baby is does not match exactly at the indicated weight!
I several parameters to consider to calculate the ideal weight of children are the height and, starting from the second year of life, the body mass index (also called BMI). To calculate the body mass index, simply divide the weight of the child (expressed in kilos) for the height (in square meters).
Starting from these data it is possible calculate the growth percentile, that is a reference scale of the parameters considered “normal” which is based on the growth curves generated by the observation of the population from birth up to 20 years. Reading the percentile tables is not immediate: in the next paragraphs we will explain how to do it.
Ideal weight of babies at birth and in the first months of life
A baby, at the time of birth, should have a healthy weight of approximately 3200-3400 grams, but it can be considered normal weight if it weighs between 2500 and 4500 grams. If the weight of the newborn is less than 2500 grams it will have to be considered underweight, if greater than 4500 grams overweight.
As paradoxical as it may seem, in the first days of life the weight of a child tends to drop by 5-7%, but - if well fed - regain the weight lost within 15 days of age. From then until the sixth month, it will tend to grow by approximately 150 grams per week. Accordingly, by the fifth month of age, her weight should be double compared to birth.
Ideal weight in children up to 10 years
Starting from the first year of age, the ideal weight of a child is approximately triple the birth weight. Starting from 18 monthsInstead, weight growth begins to slow down, with a very normal physiological stop which shouldn't scare the parent.
Between the two years (in which the weight turns out to be quadrupled compared to that of birth) and 5 years, the weight of the child increases just under 2 kg per year, while from 5 years onwards, the growth rate starts to increase little by little, by approximately 2,4 kg per year until puberty.
Height and weight they do not always grow evenly, and this can lead - around 6 years old - to a increase in body mass index (which, as we have said, depends on the relationship between weight and height).
Tables of the ideal weight of girls and boys
In the tables below we report, for informational purposes only, the range of values of the ideal weight of boys and girls in relation to age and relative height indications. As already mentioned, they are not absolute values and to evaluate the health condition and the regular growth rate of your child it is always good. talk to your pediatrician, which will take into account the specific case.
Weight - height table for girls
| Age | Weight : | Length |
| At birth | 2,3 - 4,4 kg | 44,7 - 53,6 cm |
| 1 month old baby girl | 3,0 - 5,7 kg | 49,0 - 58,2 cm |
| 2 months old baby girl | 3,8 - 6,9 kg | 52,3 - 61,7 cm |
| 3 months old baby girl | 4,4 - 7,8 kg | 54,9 - 64,8 cm |
| 4 months old baby girl | 4,8 - 8,6 kg | 57,1 - 67,1 cm |
| 5 months old baby girl | 5.2 - 9.2 kg | 58,9 - 69,1 cm |
| 6 months old baby girl | 5,5 - 9,7 kg | 60,5 - 71,1 cm |
| 7 months old baby girl | 5,8 - 10,2 kg | 62,0 - 72,6 cm |
| 8 months old baby girl | 6,0 - 10,6 kg | 63,2 - 74,4 cm |
| 9 months old baby girl | 6,2 - 11,0 kg | 64,5 - 75,7 cm |
| 10 months old baby girl | 6,4 - 11,3 kg | 65,5 - 77,2 cm |
| 11 months old baby girl | 6,6 - 11,7 kg | 67,1 - 78,5 cm |
| 12 months old baby girl | 6,8 - 12,0 kg | 68,1 - 80,0 cm |
| 15 months old baby girl | 7,3 - 12,9 kg | 71,1 - 83,8 cm |
| 18 months old baby girl | 7,8 - 13,8 kg | 73,9 - 87,4 cm |
| 21 months old baby girl | 8,2 - 14,6 kg | 76,5 - 90,7 cm |
| 24 months old baby girl | 8,7 - 15,5 kg | 79,0 - 94,0 cm |
| 27 months old baby girl | 9,2 - 16,4 kg | 80,5 - 96,0 cm |
| 30 months old baby girl | 9,6 - 17,3 kg | 82,5 - 98,8 cm |
| 33 months old baby girl | 10,0 - 18,1 kg | 84,3 - 101,6 cm |
| 36 months old baby girl | 10,4 - 19,0 kg | 86,1 - 103,9 cm |
| 4 year old girl | 11,8 - 22,6 kg | 92,7 - 112,8 cm |
| Girl 4 and a half years old | 13,54 - 23,08 kg | 96,17 - 113,41 cm |
| 5 year old girl | 14,34 - 24,94 kg | 99,35 - 117,36 cm |
| Girl 5 and a half years old | 15,17 - 26,89 kg | 102,56 - 121,32 cm |
| 6 year old girl | 16,01 - 28,92 kg | 105,76 - 125,25 cm |
| Girl 6 and a half years old | 16,86 - 31,07 kg | 108,88 - 129,08 cm |
| 7 year old girl | 17,73 - 33,37 kg | 111,87 - 132,73 cm |
| Girl 7 and a half years old | 18,62 - 35,85 kg | 114,67 - 136,18 cm |
| 8 year old girl | 19,54 - 38,54 kg | 117,27 - 139,41 cm |
| Girl 8 and a half years old | 20,53 - 41,45 kg | 119,66 - 142,45 cm |
| 9 year old girl | 21,59 - 44,58 kg | 121,85 - 145,36 cm |
| Girl 9 and a half years old | 22,74 - 47,92 kg | 123,92 - 148,26 cm |
| 10 year old girl | 23,99 - 51,43 kg | 125,96 - 151,29 cm |
| Girl 10 and a half years old | 25,35 - 55,05 kg | 128,15 - 154,58 cm |
| 11 year old girl | 26,82 - 58,72 kg | 130,72 - 158,13 cm |
| Girl 11 and a half years old | 28,38 - 62,36 kg | 133,84 - 161,76 cm |
| 12 year old girl | 30,02 - 65,9 kg | 137,44 - 165,15 cm |
| Girl 12 and a half years old | 31,7 - 69,26 kg | 141,09 - 168 cm |
| 13 year old girl | 33,41 - 72,38 kg | 144,23 - 170,2 cm |
| Girl 13 and a half years old | 35,09 - 75,2 kg | 146,56 - 171,78 cm |
| 14 year old girl | 36,7 - 77,69 kg | 148,12 - 172,88 cm |
| Girl 14 and a half years old | 38,21 - 79,84 kg | 149,11 - 173,63 cm |
| Girl 15 years old | 39,59 - 81,65 kg | 149,74 - 174,15 cm |
| Girl 15 and a half years | 40,8 - 83,15 kg | 150,15 - 174,51 cm |
| Girl 16 years old | 41,83 - 84,37 kg | 150,42 - 174,77 cm |
| Girl 16 and a half years | 42,67 - 85,36 kg | 150,61 - 174,96 cm |
| Girl 17 years old | 43,34 - 86,17 kg | 150,75 - 175,1 cm |
| Girl 17 and a half years | 43,85 - 86,85 kg | 150,85 - 175,21 cm |
| Girls 18 years old | 44,25 - 87,43 kg | 150,93 - 175,29 cm |
| 18 and a half year old girls | 44,55 - 87,96 kg | 150,99 - 175,35 cm |
| Girls 19 years old | 44,8 - 88,42 kg | 151,04 - 175,4 cm |
| 19 and a half year old girls | 44,97 - 88,8 kg | 151,08 - 175,44 cm |
| Girls 20 years old | 45,05 - 89,04 kg | 151,11 - 175,47 cm |
Weight - height table for children
| Age | Weight : | Length |
| At birth | 2,3 - 4,6 kg | 45,5 - 54,4 cm |
| Baby 1 month | 3,2 - 6,0 kg | 50,3 - 59,2 cm |
| Baby 2 months | 4,1 - 7,4 kg | 53,8 - 63,0 cm |
| Baby 3 months | 4,8 - 8,3 kg | 56,6 - 66,3 cm |
| Baby 4 months | 5,4 - 9,1 kg | 58,9 - 68,6 cm |
| Baby 5 months | 5,8 - 9,7 kg | 61,0 - 70,9 cm |
| Baby 6 months | 6,1 - 10,2 kg | 62,5 - 72,6 cm |
| Baby 7 months | 6,4 - 10,7 kg | 64,0 - 74,2 cm |
| Baby 8 months | 6,7 - 11,1 kg | 65,5 - 75,7 cm |
| Baby 9 months | 6,9 - 11,4 kg | 66,8 - 77,2 cm |
| Baby 10 months | 7,1 - 11,8 kg | 68,1 - 78,5 cm |
| Baby 11 months | 7,3 - 12,1 kg | 69,1 - 80,0 cm |
| Baby 12 months | 7,5 - 12,4 kg | 70,1 - 81,3 cm |
| Baby 15 months | 8,0 - 13,4 kg | 73,4 - 85,1 cm |
| Baby 18 months | 8,4 - 9,7 kg | 75,9 - 88,4 cm |
| Baby 21 months | 8,9 - 15,0 kg | 78,5 - 91,7 cm |
| Baby 24 months | 9,3 - 15,9 kg | 80,8 - 95,0 cm |
| Baby 27 months | 9,7 - 16,7 kg | 82,0 - 97,0 cm |
| Baby 30 months | 10,1 - 17,5 kg | 84,1 - 99,8 cm |
| Baby 33 months | 10,5 - 18,3 kg | 85,6 - 102,4 cm |
| Baby 36 months | 10,8 - 19,1 kg | 87,4 - 104,6 cm |
| Child 4 years | 12,2 - 22,1 kg | 94,0 - 113,0 cm |
| Child 4 and a half years | 14,06 - 22,69 kg | 97,48 - 114,19 cm |
| Child 5 years | 14,86 - 24,46 kg | 100,33 - 117,83 cm |
| Child 5 and a half years | 15,67 - 26,32 kg | 103,2 - 121,47 cm |
| Child 6 years | 16,5 - 28,27 kg | 106,1 - 125,11 cm |
| Child 6 and a half years | 17,37 - 30,33 kg | 109,03 - 128,74 cm |
| Child 7 years | 18,26 - 32,53 kg | 111,95 - 132,33 cm |
| Child 7 and a half years | 19,17 - 34,88 kg | 114,79 - 135,84 cm |
| Child 8 years | 20,11 - 37,42 kg | 117,5 - 139,25 cm |
| Child 8 and a half years | 21,08 - 40,15 kg | 120,04 - 142,53 cm |
| Child 9 years | 22,08 - 43,07 kg | 122,4 - 145,66 cm |
| Child 9 and a half years | 23,11 - 46,16 kg | 124,59 - 148,65 cm |
| Child 10 years | 24,19 - 49,42 kg | 126,67 - 151,53 cm |
| Child 10 and a half years | 25,35 - 52,79 kg | 128,71 - 154,37 cm |
| Child 11 years | 26,6 - 56,26 kg | 130,81 - 157,27 cm |
| Child 11 and a half years | 27,96 - 59,78 kg | 133,1 - 160,35 cm |
| Child 12 years | 29,47 - 63,31 kg | 135,66 - 163,72 cm |
| Child 12 and a half years | 31,14 - 66,82 kg | 138,55 - 167,42 cm |
| Child 13 years | 32,97 - 70,28 kg | 141,73 - 171,34 cm |
| Child 13 and a half years | 34,95 - 73,66 kg | 145,12 - 175,25 cm |
| Child 14 years | 37,07 - 76,96 kg | 148,53 - 178,82 cm |
| Child 14 and a half years | 39,28 - 80,16 kg | 151,75 - 181,8 cm |
| 15 year old boy | 41,52 - 83,24 kg | 154,61 - 184,13 cm |
| 15 and a half year old boy | 43,72 - 86,18 kg | 156,98 - 185,85 cm |
| 16 year old boy | 45,79 - 88,95 kg | 158,85 - 187,09 cm |
| 16 and a half year old boy | 47,67 - 91,51 kg | 160,25 - 187,99 cm |
| 17 year old boy | 49,29 - 93,78 kg | 161,27 - 188,63 cm |
| 17 and a half year old boy | 50,62 - 95,71 kg | 162 - 189,11 cm |
| Boys 18 years old | 51,69 - 97,25 kg | 162,5 - 189,46 cm |
| Boys 18 and a half | 52,54 - 98,38 kg | 162,85 - 189,72 cm |
| Boys 19 years old | 53,22 - 99,19 kg | 163,08 - 189,92 cm |
| Boys 19 and a half | 53,75 - 99,88 kg | 163,24 - 190,08 cm |
| Boys 20 years old | 54 - 100,78 kg | 163,33 - 190,19 cm |
The growth percentiles given by the ratio of weight to height
To calculate the ideal weight of children we use the percentile which, as we have said, is used as a reference scale to establish the weight parameters to be considered normal. this address you can download the tables with the growth percentiles drawn up byWorld Health Organization and consult them.
Se the body mass index of your child is less than the fifth percentile on the scale of values, so it is considered normal weight. If the body mass index value is included between the 85th and 95th percentile, then the child will be overweight, while if it exceeds the 95th percentile it will be obesity.
simplify consultation of the growth percentiles, although with a lesser degree of accuracy in the results, the value of the 50th percentile for the statural age (age + height). Even in these calculations, however, it is always better get help from the pediatrician.
For more scientific information on children's ideal weight, you can check out the site of the World Health Organization.
