What’s the right weight for you? The classic formulas give very different answers—and none of them take your muscle mass into account. With our ideal weight calculator, you can compare the Broca, Devine, and Hamwi formulas at a glance and get a target weight based on your body fat percentage that’s truly right for you.
What is “ideal weight”?
The ideal weight is not a medically defined measure, but rather a guideline derived from formulas developed in the 19th and 20th centuries. These formulas calculate weight based solely on height—and in some cases, gender as well.
This makes them quick and easy to use, but also imprecise: Two people who both weigh 80 kilograms and are 1.80 meters tall can look completely different, depending on how much of that weight is muscle and how much is body fat. That’s why it’s worth looking at several metrics rather than just a single number.
An Overview of the Classic Formulas
Broca Index
The best-known rule of thumb comes from the French physician Paul Broca:
Normal weight (kg) = Height (cm) − 100
To calculate the ideal weight, subtract another 10 percent (for men) or 15 percent (for women) from this result. For a height of 1.75 meters, this yields a normal weight of 75 kilograms and an ideal weight of about 67.5 kilograms for men.
The formula is easy to remember, but it quickly becomes unrealistic for very tall or very short people.
Devine Formula
The Devine formula originates from medicine and was originally developed to calculate medication dosages:
Men: 50 kg + 2.3 kg for every inch over 152.4 cm
Women: 45.5 kg + 2.3 kg for every inch over 152.4 cm
For a man who is 1.75 meters tall, this results in approximately 70.5 kilograms. These values are usually slightly higher than those of the Broca ideal weight and are considered a reliable guideline for the average height range.
Hamwi Formula
The Hamwi formula works on the same principle but places greater emphasis on height for men. It originates from the field of nutritional counseling, where it is still used today for quick assessments.
All three formulas have one thing in common: they only take your height into account. Whether you do strength training regularly or haven’t worked out in years makes no difference to the result.
Why a Range Is More Accurate Than a Single Number
Instead of a single number, the BMI provides a range. A BMI between 18.5 and 24.9 is considered a normal weight. For a person who is 1.75 meters tall, this corresponds to a range of approximately 56.7 to 76.3 kilograms—a difference of nearly 20 kilograms.
This range is precisely the point: within this range, there isn’t just one “correct” weight, but many healthy options. Our BMI calculator shows you how to calculate your BMI.
Target Weight Based on Body Fat Percentage
The most meaningful method requires one more value: your body fat percentage. This way, you’re not relying on average values, but on your own body.
Target weight = lean body mass ÷ (1 − target body fat percentage)
Here’s an example: You weigh 82 kilograms with 24 percent body fat. Your lean body mass—muscles, bones, organs, and water—is therefore about 62.3 kilograms. If you want to reach 18 percent body fat without losing muscle mass, your target weight is about 76 kilograms.
The advantage: This calculation assumes that your muscle mass remains the same. You can determine your current body fat percentage using the Body Fat Calculator.
How quickly is it realistic to reach your target weight?
As a guideline, aim for 0.25 to 0.5 kilograms per week. If you lose weight faster than that, you’ll lose a disproportionate amount of muscle mass—and with it, the very tissue that keeps your basal metabolic rate high.
For the six kilograms in the example above, that means about twelve to 24 weeks. That may sound like a long time, but it’s the period it actually takes for habits to change. The calorie burn calculator shows you how many calories you burn during your workouts, and the training heart rate calculator tells you the best intensity for your workouts.
When the Scale Stalls
This often happens, especially at the beginning of a strength training program: Your weight barely changes, but your body does. The reason is simple—you’re building muscle and losing fat, both at the same time.
That’s why it’s worth keeping an eye not only on your weight but also on your waist circumference, body fat percentage, and how your clothes fit. And it’s best to weigh yourself at the same time every day—in the morning after getting up—because water retention and meals can account for up to two kilograms over the course of the day.
What the Formulas Can’t Do
No formula takes into account your body type, muscle mass, or medical history. For athletes with a lot of muscle, the results are often too low; for older adults with little muscle mass, they’re often too high.
If you have pre-existing medical conditions, are taking medication, or want to make significant changes to your weight, discuss your goals with a doctor or a nutritionist. A body composition analysis at the gym provides significantly more accurate data than any formula.
Frequently Asked Questions / FAQ
Which formula is the most accurate?
None of the classic formulas are particularly accurate because they all rely solely on height. The calculation based on body fat percentage comes closest to reality because it takes your muscle mass into account.
Does the ideal weight also apply to athletes?
Only to a limited extent. If you’ve built a lot of muscle, the Broca formula or BMI will quickly place you in the “overweight” range, even though your body fat percentage is low. In this case, body composition is the better measure.
How often should I check my target weight?
About every three months. If your muscle mass changes, your realistic target weight will shift—either up or down.
What should my body fat percentage be?
As a general guideline, it’s about 10 to 20 percent for men and about 18 to 28 percent for women. Athletes often fall below these ranges. Very low levels aren’t healthy in the long term because the body needs a minimum amount of essential fat.
Why does the scale show a different number every day?
Fluid balance, full carbohydrate stores, salt, and intestinal contents cause your weight to fluctuate by one to two kilograms. Therefore, it’s not the single reading that’s meaningful, but the average over a week.
Editorial team at fitnessmarkt.de
Image source: #5400642 pressfoto / freepik.com
Published on: 29 September 2026