In emergency settings, medication dosages are primarily determined based on the child's weight; however, the healthcare personnel sometimes may have to make the first intervention without knowing the patient's weight, which may result in an underdose or overdose of the medication. We aimed to find a reliable method to estimate children's bodyweight, including the obese and malnourished.

We conducted the study with children between the ages of 3 and 17 years. We measured the children's bodyweight, right foot length, and mid-upper arm circumference in centimeters during their examination. We created a concise formula through regression analysis to estimate the patients' weight based on the right foot length and mid-upper arm circumference. Finally, we compared this formula to other conventional formulae.

The study included 741 patients whose average age was 8.4±3.9 (3–17) years. A high correlation was found between the patients' foot length, arm circumference, and bodyweight (R: 0.866, p<0.001 and R: 0.910, p<0.001, respectively). A single formula was created by regression analysis based on foot length and the mid-upper arm circumference without including sex and age in the calculation to make a more straightforward and faster calculation in emergency cases.

The formula created may be advantageous for reliably and easily estimating the weight of children aged 3–17 of any sex and body habitus in emergency settings without special equipment. This newly developed formula may enable a low-cost optimal level of weight estimation without the need for special equipment.