Humans have a long history of utilizing numbers as they navigate the world around them. Still, moving from simple to more complex problems requires tools like a calculator to aid in problem-solving. We’ve come a long way on the road to modern calculators.

The age calculator is designed to solve various problems that can be difficult to navigate on a typical calculator. Calculating the addition or subtraction of time is often incompatible with standard calculators due to the unit of time. Here are some of the problems you can solve with an online age calculator:

• calculating the duration between two points;
• determine how many days until an upcoming event or birthday;
• figure out how old someone is, based on their date of birth;
• identify the age of a city, building, or monument;
• learn how long ago an event occurred;
• convert between different time units, including seconds, minutes, and hours.

You can use the Body Mass Index (BMI) calculator to compute your BMI value and the corresponding weight status based on your age. The calculator uses the metric system of units in the “Metric Units” tab by default. You can select the U.S. system of units on the “US Units” tab or use the unit converter on the “Other Units” tab. The Ponderal Index is computed together with the BMI.

BMI Overview

BMI measures an individual’s degree of fatness or leanness regarding weight and height. It can also provide information about the tissue mass in a person’s body. You can use it to assess the proportionality of the weight-to-height ratio.

The results of a BMI calculation determine whether a person is obese, overweight, average weight, or underweight. BMI ranges are sometimes broken down into subgroups, such as very underweight or seriously obese. These BMI ranges vary by factors such as region and age.

Obesity or malnutrition can have severe consequences on one’s health. And while BMI is an imperfect indicator of healthy body weight, it is a helpful indicator of whether additional testing or action is needed. For further information on BMI classifications and calculations, see the table below.

BMI Limitations

Despite its extensive use as a reliable predictor of healthy body weight, the body mass index (BMI) has several limitations. These include not considering the entire body makeup. The diversity of body types and the distribution of fat, muscle, and bone mass make it necessary to use BMI with other indicators.

In adults:

Online calculators provide a general estimate of BMI based on height and weight, but they don’t account for specific factors that can influence its accuracy. BMI doesn’t differentiate between weight from muscle and weight from fat, so it’s not a direct measure of body fat. Additionally, various factors, such as age, gender, muscle mass, levels of exercise, and others, can influence BMI readings and their interpretations.

Let’s take the example of a passive older person who sits or lies down most of his life. He has a significant excess fat, but he is not overweight overall. In terms of objective health, this person may not be relatively healthy, but in terms of BMI, he might be normal.

The opposite is true of bodybuilders, who have powerful muscles. Muscle is heavier than fat, yet it takes up less volume. Regarding BMI, many bodybuilders may be either near the upper limit of normal weight or be considered overweight. At the same time, they will be in excellent health. A person can look more trim and still be heavier with a solid body mass.

CDC (Centers for Disease Control and Prevention) data shows that:

• At the same BMI level, women tend to have more body fat than men;
• Older people tend to have more body fat than younger people with the same BMI;
• Athletes undergoing intense training may have a higher BMI because of significant muscle mass.

In adolescents and children:

The same variables responsible for limiting the efficacy of BMI in adults also apply to adolescents and even children. Height and the level of sexual development may influence the BMI and body fat percentage.

In obese children, BMI is a stronger predictor of excess body fat than in overweight children. Their BMI can be caused by a high fat- or fat-free mass (all body components other than fat, such as water, organs, muscle, and so on). In lean children, the difference in BMI may also be due to fat-free mass.

For the general population, BMI can be a useful indicator for potential health risks associated with being underweight, overweight, or obese. However, due to its limitations, BMI should be used as one of several tools for assessing an individual’s health and body weight, always in conjunction with other assessments and personalized health evaluations.

BMI Formula

Below are the equations used to calculate BMI in the International System of Units (SI) and the United States General System (USC). They use a person who is 5 feet 10 inches tall and weighs 160 pounds as an example.