Ideal body weight calculator: find your healthy weight range

Published on May 14, 2026

Ever wondered what your ideal body weight is?

Maybe you’ve seen formulas tossed around in fitness forums, or your doctor mentioned it in passing.

Truth is, there isn’t a single “perfect” number for anyone — but knowing your healthy weight range can give you a useful reference point for your overall health and well-being.

That’s where our calculator comes in. It’s a simple, free tool that helps you estimate your ideal body weight, compare it to your actual body weight, and explore the role of factors like muscle mass, body composition, and lifestyle in achieving your ideal body weight.

Ready to dive in?

Ideal weight calculator

What this calculator does

This calculator is a simple step to a deeper understanding of your body. It estimates your ideal body weight using methods trusted in both healthcare and fitness.

Here’s what’s special about our calculator:

You can see your results across multiple formulas, giving you a range rather than a single number.

That’s useful because no one’s ideal body weight is a single number on a scale. We all have a range within which our weight will naturally fluctuate while remaining perfectly healthy.

Methods explained

Our calculator uses four main formulas to estimate ideal body weight, each with its own history and quirks. Let’s break them down.

Devine formula

The Devine formula.[1] is one of the most well-known methods. Originally created to help doctors determine medication doses for obese patients, it calculates ideal weight using just your height and sex.

It’s simple and widely referenced, making it a solid choice if you want a quick estimate. The downside is that it doesn’t account for muscle mass or bone structure, so if you’re built bigger or carry a lot of muscle, your actual ideal body weight might be higher than the number it gives.

Robinson formula

The Robinson formula.[2] is similar to Devine but slightly tweaks the numbers based on updated population data. For some adults, it produces a slightly lower ideal body weight than Devine. It’s helpful if you want a number that feels a little more in line with modern body composition trends.

Miller formula

If you’re aiming for a more well-rounded estimate, the Miller formula.[3] might be your go-to. It tends to produce slightly leaner numbers and can be useful if your goal is weight loss or fine-tuning a healthy BMI.

Hamwi formula

The Hamwi formula.[4] is a favorite in nutrition nutrition and medical literature. It calculates ideal body weight using height and sex, and it’s commonly referenced when evaluating healthy weight ranges for adults. It’s easy to use and gives clear results, but like the others, it won’t account for someone with bigger muscles or a larger frame.

Ideal weight ranges explained

Your ideal body weight isn’t a single number.

To illustrate why that matters, let’s imagine for a moment that it is.

Let’s say your ideal body weight was 145.7 lbs. What knots would you have to tie yourself in to hit that extremely specific goal weight? And then to stay there?

Body weight naturally fluctuates day to day and season to season.

For instance, if you ate more salt yesterday, you may weigh more this morning. If you just worked out, you may weigh more or less than when you started. If you’re dehydrated, or well-hydrated, your weight will change. These are all temporary changes and accommodated within your healthy weight range.

Then there are more permanent shifts. Perhaps you go through a season of higher stress and your weight drops. Or you can’t hit the gym as hard for a few months, and your weight climbs. In winter, we naturally gain weight which we often lose in summer, because of the weather and seasonal food trends. Again, all of this may be accommodated within a healthy weight range, because as these influences shift with time, your weight does too.

That’s why the calculator doesn’t just give one number. Having a healthy range allows you to find your sweet spots within a wider window, and allows your body to stay responsive to the world around it.

How to use the ideal body weight calculator

The calculator is simple:

Select your sex (male or female).
Choose your units: metric (cm) or imperial (feet/inches/weight in pounds).
Enter your height.
Optionally, enter your current weight for a comparison.
Choose a formula or leave it on “All formulas” to see every calculation.
Click “Calculate”, and voilà — your ideal body weight range appears.

If you entered your current weight, the tool will show whether you’re above, below, or within the healthy range, without judgment, like this: “You are 5 lbs above your ideal range.”

Understanding the results

As you review your range, what do you notice?

Perhaps your ideal body weight is showing as lower than your actual weight and that makes sense to you. You have some body fat to lose and you’re actively aiming to achieve weight loss. Great! Now you have a science-backed target to shoot for.

But what if your ideal body weight shows as a higher weight than you are now? Well, perhaps gaining weight would boost your health, and/or your ideal body composition includes having more muscle. Being a healthy weight means having enough body mass to feel good and function well, and weight gain is a perfectly valid goal.

Maybe your ideal body weight is showing as higher or lower than you currently weigh, but you feel great and your health markers show your actual body weight is your sweet spot. You’re working out, you’re eating well, and your sleep and stress management habits are strong. If so, rely on your inner wisdom and personal data over anything an online calculator tells you.

Remember, these ideal body weight calculations are just estimates. There are lots of factors at play when it comes to the number you ideally want to see on the scale.

Factors that influence ideal weight

Your body weight and health will always be influenced by physical factors like your muscle mass, bone structure, body fat, age, height, and gender, like this:

Muscle weighs more than fat, so having a higher muscle mass makes you heavier.[5]
Taller people with larger bone structures naturally weigh more.[6]
Active adults who strength train often weigh more due to higher amounts of muscle tissue.[7]
Active adults who focus more on endurance cardio may weigh less due to lower amounts of muscle tissue.[8]
Men and women have different sex hormone levels, which affect muscle growth, body fat storage, and overall body composition.[9]
Age affects ideal body weight as metabolism tends to slow with age, which may increase healthy weight range.[10]
Age also affects our hormones. This changes body fat levels, muscle mass, and body composition, and can make us either heavier or lighter, depending on our starting point.[11]

While ideal body weight formulas give you a number based on height and sex, they don’t account for muscle versus fat, bone density, or overall body composition. That means that two people of the same height could have the same ideal body weight but very different health profiles.

They also don’t account for lifestyle. So two men of the same age and height will have the same ideal body weight according to our formulas. But if one’s a professional rugby player while the other is an accountant, do they really share the same “ideal” body weight? Not really, given the tasks they ask their bodies to engage in. A rugby player ideally needs to be heavier.

Bear all this in mind as you review your results.

Ideal body weight and body mass index (BMI)

We can’t wrap up our discussion about ideal body weight without talking about body mass index (BMI).

BMI is calculated as weight (kg) divided by height squared (m²), and a typical healthy BMI falls between 18.5 and 24.9.

But BMI has several limitations. It doesn’t distinguish between lean muscle and fat, account for age or genetics, and can misrepresent health risks in high-performance athletes or people from different racial and ethnic groups.

For instance, someone with a lot of muscle might appear “overweight” by BMI standards, even though their body fat and visceral fat visceral fat are within a healthy range.

Speaking of visceral fat, where fat is stored matters. Carrying extra fat around the waist is more strongly linked to health risks, like heart disease and diabetes, than fat stored in the hips or thighs.[12] That’s why measures like waist-to-hip ratio (WHR) or waist-to-height ratio (WHtR) give a useful picture of your health, one that BMI or ideal body weight cannot.

If you’re curious for a truly personalized assessment of your body weight and metabolic health, we recommend consulting a healthcare provider. You can get more precise insights into your body composition with tests like skinfold measurements or bioelectrical impedance analysis (BIA), which assess body fat percentage versus lean mass. That, along with a health screen that assesses your lipid profile, blood sugar levels, etc., can help determine how close you are to achieving what is healthy for your unique body.

Simple’s expert opinion and final thoughts

Ultimately, tools like our ideal body weight calculator give you an estimate to use as a guide. From there, you can make more informed choices about your nutrition, activity, and health that get you closer to your optimum body composition and lifestyle.

The best indicator of your ideal body weight, though, is always how you feel in your body. What kind of eating habits and workouts give you energy and joy? How does your body change when you improve your nutrient density or sleep patterns? For the best results, seek health not just in the numbers, but in your quality of life.

Want a personalized plan you can use to improve your health, eating, and fitness habits? Take our Simple quiz. We’ll get you started (often the hardest part!), then support you to keep going till you reach your goals.

FAQ

Which ideal weight formula is the most accurate?

No formula is perfect. Each provides a general guideline, so it’s helpful to look at multiple formulas together.

Why do different formulas give different results?

Formulas were created for different populations and purposes, and take different factors, like height, sex, and body composition, into account. Those differences lead to variations in results.

Does muscle mass affect ideal weight?

It does. Someone with significant muscle mass may weigh more than the ideal weight range suggested, but still be healthy.

Is ideal weight the same as healthy weight?

Yes. Ideal weight is a measure that suggests the weight range within which your body would be healthiest and have the lowest associated health risks.

How often should I reassess my ideal weight?

Check in with yourself once a year, or as / when your lifestyle or health conditions change.

How do I calculate ideal body weight?

Use our calculator above — it’s really simple!

Is 170 lbs heavy for a woman?

Not necessarily — it depends on height, age, body composition, and other factors. Check your healthy weight range to see where you land.

Is 200 lbs overweight for 5’8”?

At 5’8”, 200 lbs falls into the obesity range based on BMI calculations. However, BMI doesn’t tell the full story. Factors like muscle mass, body composition, age, and overall health matter too. For example, someone with a high amount of muscle may weigh 200 lbs without carrying excess body fat. Ideal weight is best viewed alongside body composition and other health markers, not BMI alone.

Is ideal body weight still used today?

Yes! Healthcare providers, nutritionists, and fitness professionals still use it to help adults determine general health guidelines, plan weight management, and assess health risks.