A BMI of 20 is a healthy BMI for women and men as far as the the body mass index goes. But what does this actually mean for your health and body composition?
Well, since BMI doesn’t measure body fatness or muscle mass, it can’t tell you much about your body composition or health status, especially a BMI that’s normal (i.e., far from being severely underweight or overweight).
See How Your BMI Stacks Up:
Is a BMI of 20 good for a female?
Is a BMI of 20 good for females? Yes, a BMI of 20 is good for women because a 20 BMI is considered normal by the world’s leading health authorities. 
Body mass index is a useful screening tool for identifying people who might be at risk of disease. However, BMI can’t tell you anything about your body composition, something that’s especially true for those with a 20 BMI.
Sure, if you have a very high BMI, then you almost certainly have way too much body fat. In other words, BMI is more useful for identifying people who are at serious risk.
But if you have a BMI of 20, then you could have relatively little muscle mass but quite a lot of body fat, which certainly isn’t ideal for achieving optimal health (or anything close to it).
Is a 20 BMI good for a male?
Is a 20 BMI good for a male? While body mass index can’t measure a man’s body fatness or muscle mass, a BMI of 20 is a sign that a male has a healthy body weight.
Some men with a 20 BMI have a low body fat level and a decent amount of muscle mass. For a BMI 20 score, this is the ideal physique.
On the other hand, you have those men with what researchers call sarcopenic obesity.
This condition is most commonly observed in elderly men (but is by no means exclusive to older individuals) and is characterized by low levels of muscle mass and a relatively high body fat level.
So a man might have a waist that’s too large but really skinny legs. In this case, he might well have a BMI of 20, but his body composition is far from ideal and could be an indication that his diet is lacking important nutrients.
What does a BMI of 20 look like?
Although it’s impossible to say what a person with a BMI of 20 looks like all the time, there are two general categories that a person will fall into.
One is low body fat and normal levels of muscle mass. This is the healthier of the two categories.
Second, a person might have low levels of muscle mass and a relatively high body fat level, which is often termed “skinny fat” in the fitness community.
Of course, many people fall somewhere in between these two categories and have, as a result, a very average body type.
Is a 20 BMI too skinny?
A 20 BMI is one and a half BMI points above the underweight category. So, based on the score, a body mass index of twenty is definitely not too skinny.
However, if a person with a 20 BMI lacks muscle mass, then they might have a skinny physique that could benefit from more muscle mass.
Increasing your muscle mass not only makes you look better aesthetically but also gives you more functional strength, higher energy levels, and a greater resistance to muscular injuries.
Common BMI 20 scores
Most of the time, you’ll get a precise BMI score rather than a rounded number. Many of the following scores are naturally similar, but it can be useful to see where you fit in on the BMI scale.
A 20.1 BMI is considered normal and healthy because it’s above the underweight category while being far away from an overweight classification.
If you have a 20.2 BMI, then your body weight is considered to be in the healthy range. Of course, a BMI of 20.2 doesn’t tell you much about your health, but having a 20.2 body mass index is still a good starting point for improving your health and fitness.
A 20.3 BMI is healthy because it’s on the lower end of the normal range. People who have a BMI of 20.3 are typically quite a bit slimmer than average, and they commonly have a relatively low body fat level.
A BMI of 20.4 is normal for men and women and indicates that a person has a healthy body weight. Unfortunately, as with any body mass index score, a 20.4 BMI doesn’t tell you much else. 
A 20.5 BMI is a full 2 BMI points above the underweight cut-off point and, as such, is well within the healthy range. If you have a BMI of 20.5, then you probably don’t need to lose weight or gain weight unless you need more muscle mass.
Those with a BMI of 20.6 are well within the healthy range and likely have a slim build. While some people with a 20.6 BMI have too much body fat, many also have good levels of muscle mass and minimal adiposity.
A 20.7 BMI score is much lower than average and is comfortably in the healthy range for males and females. If you have a BMI of 20.7, then while you’re not guaranteed to have good health, you likely don’t need to worry about your body weight.
If you have a BMI of 20.8, then you can be happy that you have a healthy body weight. It’s good to have a 20.8 BMI because it means that you don’t need to spend time losing or gaining weight; you can focus on other areas of your health instead.
A 20.9 BMI is almost out of the BMI 20 scores and yet, is perfectly normal. Those who have a BMI of 20.9 very likely don’t need to worry about their body weight being too low or too high, although some people may need to lose body fat and/or gain muscle mass.
Conclusion: Is a BMI of 20 skinny or fat?
A BMI of 20 is, in general, neither skinny nor fat; it’s normal and usually results in a fairly average body type.
To be sure, you can still have excess body fat while registering a 20 BMI. And, by the same token, you can have good levels of muscle mass and a very low body fat percentage while registering a BMI of 20.
So, while body mass index is useful for assessing your weight, it can’t measure your body composition.
- Weir CB, Jan A. BMI Classification Percentile And Cut Off Points. [Updated 2022 Jun 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK541070/
- Khanna, D., Peltzer, C., Kahar, P., & Parmar, M. S. (2022). Body Mass Index (BMI): A Screening Tool Analysis. Cureus, 14(2), e22119. https://doi.org/10.7759/cureus.22119