A better goal weight than a height chart comes from your own lean mass: goal weight = lean mass ÷ (1 − target body fat). For example, 64.8 kg of lean mass at an 18 percent body fat target gives about 79 kg.
"What should I weigh?" is one of the most searched health questions there is. Most answers give you a single number based only on your height. That number can be useful as a rough guide, but it ignores the thing that matters most: what your weight is made of.
Where the classic formulas come from
The well-known ideal weight formulas, such as Devine (1974), Robinson and Miller, were created to help doctors dose medicines, not to tell people how they should look. They use only height and sex. Two men who are both 178 cm get the same "ideal" weight, even if one lifts weights and the other never exercises.
The healthy BMI range, 18.5 to 24.9, gives a wider band. For someone 178 cm tall, that is about 59 to 79 kg. A 20 kg range is honest about how different healthy bodies can be, but it is not much help in choosing a goal.
A better way: start from your lean mass
Your weight is lean mass (muscle, bone, organs, water) plus fat. When you diet well and train, your lean mass stays about the same and the fat comes down. So a better goal is:
Goal weight = lean mass ÷ (1 − target body fat)
Example: a man weighs 90 kg at 28 percent body fat. His lean mass is 90 × 0.72 = 64.8 kg. If he aims for 18 percent body fat: 64.8 ÷ 0.82 = about 79 kg.
That goal belongs to him. A more muscular man the same height would get a higher one, and that is correct.
You can find your body fat with a tape measure and our body fat calculator, then use the ideal weight calculator on this page to try different targets.
Your ideal weight is the weight where you are healthy, strong and able to stay there without fighting every day.
Choosing your target body fat
Common reference points:
- Men: 14 to 17 percent is fit; 18 to 24 percent is average. Below about 10 percent is hard to keep for most people.
- Women: 21 to 24 percent is fit; 25 to 31 percent is average. Going much below about 18 percent can affect hormones and health.
If you are starting from a high body fat, set your first goal in the average range. You can always set a new goal after you get there.
Other signs you are at a good weight
- Your waist is less than half your height.
- Your blood pressure, blood sugar and cholesterol are in the healthy range.
- You sleep well, have steady energy, and can train hard.
- You can keep this weight without constant hunger or strict rules.
Getting there
Whether you want to lose or gain, the tools are the same: a small, steady calorie deficit or surplus, enough protein, strength training and more daily steps. Aim to lose about 0.5 to 1 percent of your bodyweight a week, or gain about 0.25 to 0.5 percent a week if you are building muscle.
Sources
- Where ideal-weight formulas come from (drug dosing): Pai and Paloucek, 2000
- World Health Organization, obesity and overweight: who.int
The takeaway
Ignore single-number charts. Work out your lean mass, choose a realistic body fat target, and let the maths give you a goal that fits your own body. In the Shulah app you set your goal weight, and it is broken into small milestones, each with a date, so the big number feels reachable.