About the calculation
How is ideal weight calculated on this site?
We average four published clinical formulas — Devine, Robinson, Miller and Hamwi — based on your height and gender, then adjust the result by ±10% depending on whether your body frame is small, medium or large.
Why do you use four formulas instead of one?
Each formula was developed independently and produces a slightly different number. Averaging them smooths out the differences between individual formulas and gives a more balanced estimate than relying on any single one.
Why does frame size matter for ideal weight?
Bone structure varies naturally between people of the same height. Someone with a larger frame carries more skeletal weight and is healthy at a higher number than someone with a smaller frame at the identical height.
How do I measure my wrist for frame size?
Wrap a soft tape measure around the narrowest point of your wrist, just below the wrist bone, and enter the circumference in centimetres. The calculator compares this to your height to estimate your frame automatically.
Accuracy & limitations
How accurate is an ideal weight calculator?
It's a useful estimate, not a precise medical measurement. The underlying formulas were developed decades ago from limited population data and don't account for individual muscle mass, ethnicity or overall body composition.
Is ideal weight the same as BMI?
No. Ideal weight gives one specific number adjusted for height, gender and frame size. BMI gives a wider healthy-weight range for a given height without factoring in frame size or gender at all. See our full explanation.
Is this calculator suitable for athletes or bodybuilders?
Not precisely — these formulas don't distinguish between muscle and fat, so a muscular, low-body-fat person can weigh well above their "ideal weight" figure and still be lean and healthy. Body fat percentage is a more useful metric in that case.
Can I use this during pregnancy?
No. These formulas assume a non-pregnant adult baseline. Please speak with your doctor or midwife about healthy weight gain during pregnancy and postpartum recovery.
The goal timeline
How is the goal timeline calculated?
We divide the difference between your current weight and your ideal weight by a safe rate of 0.5 kg per week, giving an estimated number of weeks and a target date.
Is 0.5 kg per week actually a safe rate?
For most healthy adults, losing or gaining around 0.5 kg (about 1 lb) per week through gradual diet and lifestyle changes is generally considered a sustainable pace. Faster rates for extended periods are best discussed with a doctor or dietitian.
Does my current weight get stored anywhere?
No. All calculations happen directly in your browser — your inputs are never sent to or stored on our servers.