Ideal Body Weight Calculator (According to Height & Age)

Updated in February 2023

A person's ideal body weight is often calculated using height, sex and weight. The main benefits of staying within your ideal weight are characterized by disease prevention, as an ideal body weight can prevent the development of obesity, hypertension, diabetes, or even malnutrition (when the person's weight is too low).

To calculate your ideal body weight, you need to calculate your BMI (Body Mass Index), which your age, weight, and height takes into consideration. It's important to mention that BMI is just a reference, as it does not take your fat, muscle, or water composition into account.

If you a have a higher muscle mass, for example, or suffer from fluid retention, calculating your ideal weight using your BMI may not be appropriate or accurate. In this case, a formal nutritional assessment by a health care professional is most recommended.

How much should I weigh?

To calculate your ideal body weight, enter your details below:

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This calculator provides a rough idea of how much you should weigh according to your height, age and sex. However, there are other important factors that should be taken into consideration, such as fat, muscle, and water composition.

If you have any concerns about your weight, you are advised to see a registered dietitian for a formal assessment. He or she will take many factors into consideration such as your lifestyle, your health history, your current activity status and your fat, muscle, and water composition.

Body weight for children

The following outlines reference ranges of average weight for girls up to the age of five years old:

AgeWeightAgeWeightAgeWeight
1 month7 - 11 lb 6 months14 - 18 lb 18 months20 - 26 lb
2 months10 - 13 lb 8 months15 - 20 lb 2 years22 - 29 lb
3 months11- 15 lb 9 months16 - 21 lb 3 years24 - 35 lb
4 months12 - 16 lb 10 months16 - 21 lb 4 years31 - 41 lb
5 months13 - 17 lb 11 months17 - 22 lb 5 years34 - 47 lb
6 months14 - 18 lb 12 months17 - 22 lb ------ ------

The following outlines reference ranges of average weight for boys up to the age of five years old:

AgeWeightAge Weight Age Weight
1 month7 - 11 lb 7 months16 - 20 lb 18 months22 - 27 lb
2 months11 - 14 lb 8 months17 - 21 lb 2 years24 - 30 lb
3 months12 - 16 lb 9 months18 - 22 lb 3 years28 - 36 lb
4 months14 - 17 lb 10 months18 - 22 lb 4 years32 - 41 lb
5 months15 - 19 lb 11 months19 - 23 lb 5 years35 - 47 lb
6 months15 - 19 lb 12 months19 - 24 lb ------ ------

With infants, ideal weight is related to the nutritional status and intake rather than height, and therefore weight is guided by age in months. The ratio between weight and height is only used in children that are two years old or older.

How to achieve your ideal body weight 

If you are not at your ideal weight, you are advised to visit a registered dietitian to start a diet adapted to your goals. You should also visit a personal trainer to create a customized exercise plan.

Achieving your ideal weight will depend on whether you are trying to lose or gain weight.

1. If you are above your ideal body weight 

If you are overweight and want to get down to your ideal body weight, you should increase your intake of healthy food that is rich in fiber and low in calories. Examples include eggplant, ginger, salmon, and flaxseed. These foods help to accelerate metabolism and reduce anxiety, encouraging weight loss. See a list of foods rich in fiber that you can include into your daily diet.

To achieve your goal faster, you should engage in regular exercise so that you can increase energy expenditure and metabolism. A dietitian can indicate some teas and natural supplements, if necessary, to encourage weight loss and decrease anxiety. Learn some nutritional tips and exercise plan to lose weight in 1 week.

In cases of severe obesity, the doctor may prescribe medications that help with weight-loss, to be taken in conjunction with a suitable diet and a physical activity plan. Another option is bariatric surgery, which is indicated for those who struggle with obesity and are not able to lose weight through traditional methods.

In addition to knowing your ideal weight, it's also important to know your waist-hip ratio, as this can predict your risk for heart diseases, diabetes and stroke. Learn more about healthy weight loss foods to include in your diet. 

2. If you are below your ideal weight

If your BMI is low and you are looking to gain weight, you should consult a dietitian for formal assessment and to get you started on a nutrition plan adapted to your individual needs.

Firstly, your increase in weight should be done in a healthy manner. This means you should gain weight through muscle hypertrophy and not through fat accumulation in the body. Therefore, having fast food such as pizza, fried food, hot dogs, and hamburgers is not the best option if you need to gain weight in a healthy way, as this type of fat can get stored in the arteries, increasing the risk of heart disease.

To increase muscle mass, it's important to increase your intake of protein with foods like eggs, cheese, dairy products, chicken, and salmon. You should also eat every three hours to increase calorie intake. See a list of high-protein foods to include in your daily diet.

In some cases, low weight can be due to a lack of appetite related to physical or emotional distress and the doctor may order tests to identify what the cause could be. 

Check out other tips on how to gain weight and muscle mass.