What This Ideal Weight Calculator Tells You
Enter your height and the calculator gives you a personalised healthy weight range based on four widely-used medical formulas — plus your BMI (body mass index) zone. It takes about ten seconds and nothing leaves your browser.
How to Use It
- Enter your height in centimetres (cm).
- Select your sex — most formulas produce slightly different ranges for male and female bodies.
- Hit Calculate. You'll see your ideal weight range, your BMI-based healthy weight band, and results from each formula side by side.
- Compare the numbers and read the notes below — they explain what the range means and where it has limits.
Worked Example
Say you are 168 cm tall (female). Here's what each method suggests:
| Formula | Ideal weight at 168 cm (female) |
|---|---|
| Robinson (1983) | 57.8 kg |
| Miller (1983) | 57.1 kg |
| Devine (1974) | 59.0 kg |
| Hamwi (1964) | 58.6 kg |
| Healthy BMI range (18.5–24.9) | 52.2 – 70.3 kg |
Notice the four formulas land within a few kilograms of each other (~57–59 kg). The BMI-based range is broader (52–70 kg) because it reflects the full band of weights that fall in the 'normal' zone for that height. All five are estimates — your ideal weight depends on factors like muscle mass, bone density, and body composition that no single number can capture.
This is educational information, not medical advice. For personal health decisions, please see your doctor or a registered dietitian.
How Ideal Weight Is Calculated
Most formulas start with a base weight for the first 5 feet (152.4 cm) of height, then add a fixed amount per centimetre above that. BMI works differently — it divides weight by height squared.
The Four Main Formulas
All four use height in centimetres (cm) and produce weight in kilograms (kg). The abbreviation H = height in cm.
Robinson (1983) — female:
Ideal weight = 49 + 1.7 × ((H − 152.4) / 2.54)
Robinson (1983) — male:
Ideal weight = 52 + 1.9 × ((H − 152.4) / 2.54)
Miller (1983) — female:
Ideal weight = 53.1 + 1.36 × ((H − 152.4) / 2.54)
Miller (1983) — male:
Ideal weight = 56.2 + 1.41 × ((H − 152.4) / 2.54)
Devine (1974) — female:
Ideal weight = 45.5 + 2.3 × ((H − 152.4) / 2.54)
Devine (1974) — male:
Ideal weight = 50 + 2.3 × ((H − 152.4) / 2.54)
Hamwi (1964) — female:
Ideal weight = 45.4 + 2.2 × ((H − 152.4) / 2.54)
Hamwi (1964) — male:
Ideal weight = 48.1 + 2.7 × ((H − 152.4) / 2.54)
BMI-Based Healthy Weight Range
BMI stands for body mass index — a number that compares your weight to your height. It is widely used as a quick population-level screen, not a precise individual measure.
BMI = weight (kg) ÷ height (m)²
Healthy weight range (kg) =
lower limit: 18.5 × (height in metres)²
upper limit: 24.9 × (height in metres)²
| BMI range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal / healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
Source: World Health Organization — Obesity and overweight fact sheet.
Formula Comparison at a Glance
The table below shows how four formulas compare for 168 cm (female), alongside the BMI healthy range. These are estimates — frame size, muscle mass, age, and ethnicity all affect what a healthy weight looks like for a specific person.
| Method | Year | Originally developed for | Result at 168 cm (female) |
|---|---|---|---|
| Hamwi | 1964 | Clinical diabetes patients | 58.6 kg |
| Devine | 1974 | Pharmacy drug dosing | 59.0 kg |
| Robinson | 1983 | Refinement of Devine | 57.8 kg |
| Miller | 1983 | Refinement of Devine | 57.1 kg |
| Healthy BMI (18.5–24.9) | — | Population health screening | 52.2 – 70.3 kg |
Educational only — not medical advice. Speak to a doctor or dietitian before making changes to your diet or exercise plan.
How to Read Your Result — and Its Limits
The formulas above were originally created for drug dosing in clinical settings, not as personal fitness targets. They give a useful reference point, not a prescription.
BMI and these formulas do not distinguish muscle from fat. A very muscular person may show a 'high' BMI even at low body fat. Older adults, pregnant people, and certain ethnic groups may need different reference ranges — the NIH/NHLBI and many clinical bodies note these limitations openly.
Use the result as a starting point for a conversation with your GP or dietitian, not as a pass/fail score.
Practical Tips for a Healthy Weight
- Move in a way you enjoy. Consistent activity — walking, swimming, cycling — matters more than perfection. Even 20–30 minutes most days makes a real difference.
- Eat mostly whole foods. Vegetables, legumes, wholegrains, and lean protein keep you fuller longer and supply the nutrients your body needs.
- Drink enough water. Thirst is often confused with hunger. Aim for around 1.5–2 litres a day unless your doctor advises otherwise.
- Prioritise sleep. Poor sleep raises hunger hormones (ghrelin) and makes healthy choices harder. Seven to nine hours for most adults is a reliable target.
- Small changes beat big ones. A modest, sustainable calorie adjustment — not a crash diet — is what the research consistently supports for long-term weight management.
- Track progress gently. Weighing yourself once a week at the same time (morning, after waking) gives a more honest picture than daily fluctuations.
If you're thinking about your calorie needs alongside your weight goal, a TDEE (total daily energy expenditure) calculator can estimate how many calories you burn each day, which is the starting point for any evidence-based eating plan.
Your Privacy
All calculations happen entirely in your browser. No height, weight, or personal data is sent to any server or stored anywhere. You can use this tool with complete confidence.
One-line takeaway: Your ideal weight is a range, not a single number — use the calculator above to find yours, then talk to a professional if you want a personalised plan.