Calculadora de Peso Ideal para Crianças
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
1-5 anos: 2·idade + 8 ; 6-12 anos: 3·idade + 7
About this calculator
The Ideal Weight Calculator for Children is a practical tool that estimates the average expected weight for children aged 1 to 12 years, based on simple growth formulas. For children aged 1 to 5 years, the formula is: ideal weight (kg) = 2 × age (years) + 8. For children aged 6 to 12 years, the formula is: ideal weight (kg) = 3 × age (years) + 7. These formulas are widely used in pediatrics as a quick reference, but they do not replace individualized medical evaluation.
How to use: simply enter the child's age in years and click calculate. The result shows the estimated ideal weight. For example, a 4-year-old child has an ideal weight of 16 kg (2×4+8), while a 10-year-old has 37 kg (3×10+7). This calculator is useful for parents, caregivers, and health professionals who want an initial reference to monitor child growth.
When to use: ideal for routine check-ups, school screenings, or to check if the child's weight is within the expected range for their age. It is important to remember that ideal weight can vary based on height, gender, and body type. The calculator should not be used to diagnose malnutrition or obesity, only as general guidance.
Precautions: these formulas are approximations and do not consider individual differences such as genetics, diet, and activity level. Always consult a pediatrician for a complete evaluation. The calculator is intended for healthy children without medical conditions affecting weight. For children outside the age range (under 1 year or over 12 years), other references are more appropriate.
Frequently asked questions
Does the calculator work for children of any age?
No, it is intended only for children aged 1 to 12 years. For infants under 1 year or teenagers over 12, other tables and formulas are more appropriate.
Is the result the same for boys and girls?
Yes, the formulas used do not differentiate by sex. In practice, boys and girls may have slightly different weights, but this calculator provides a general estimate.
Can I use this calculator to diagnose obesity or malnutrition?
No, it serves only as a reference. Diagnosis should be made by a pediatrician, considering height, percentile, and health history.
Why do the formulas change at age 6?
Because the growth rate is different: younger children gain weight more linearly, while older children have a faster gain. At age 6, the formula adjusts to this change.
What if the child's actual weight is very different from the ideal?
Consult a pediatrician. Differences can be normal due to genetic or developmental factors, but professional evaluation is essential to rule out problems.