What Is a Healthy Weight Calculator?
A healthy weight calculator works out the range of body weight, for your exact height, that falls within the NHS-defined healthy BMI band of 18.5 to 24.9. Rather than giving you a single BMI number to interpret, it flips the calculation around and tells you directly: "for someone your height, a healthy weight is between X and Y kilograms (or stone)."
This is genuinely useful because most people find a weight range in kilograms or stone far easier to relate to than an abstract BMI figure. If you're 1.70 metres tall, for example, our calculator will tell you that a healthy weight for you sits between roughly 53.5kg and 72kg — a concrete target rather than a number on a scale that means little on its own.
Behind the scenes, the calculator still uses the same trusted BMI formula relied on by GPs and NHS clinicians across the UK: weight in kilograms divided by height in metres squared. It simply presents the result the other way round, alongside your current BMI category, so you get both pieces of information in one place.
Healthy Weight Range Table (NHS BMI Bands)
The table below shows approximate healthy weight ranges for common UK adult heights, based on the NHS healthy BMI band of 18.5–24.9. Use the calculator above for a precise figure tailored to your exact height.
| Height | Healthy Weight Range (Metric) | Healthy Weight Range (Imperial) |
|---|---|---|
| 1.55m (5'1") | 44.4 – 59.8 kg | 6st 13lb – 9st 6lb |
| 1.60m (5'3") | 47.4 – 63.7 kg | 7st 6lb – 10st 0lb |
| 1.65m (5'5") | 50.4 – 67.8 kg | 7st 13lb – 10st 9lb |
| 1.70m (5'7") | 53.5 – 71.9 kg | 8st 6lb – 11st 4lb |
| 1.75m (5'9") | 56.7 – 76.2 kg | 8st 13lb – 12st 0lb |
| 1.80m (5'11") | 59.9 – 80.6 kg | 9st 6lb – 12st 9lb |
| 1.85m (6'1") | 63.3 – 85.2 kg | 9st 13lb – 13st 6lb |
Important for BAME communities: The NHS recommends lower BMI thresholds for people of South Asian, Chinese, and Black African or Caribbean heritage. For these groups, overweight is defined as a BMI of 23 or above, so the top of your healthy weight range should be calculated using 23 rather than 24.9. This reflects research showing higher health risks at lower BMI values for these populations.
Healthy Weight Calculator: NHS Basis and Accuracy
This calculator is built on the NHS BMI classification system, the same screening approach used in GP surgeries throughout England, Scotland, Wales, and Northern Ireland. It is not, however, a substitute for a full clinical assessment — BMI-derived weight ranges cannot account for muscle mass, bone density, or how fat is distributed across your body.
A very muscular person, for instance, may weigh more than their "healthy range" suggests while still carrying very little body fat. Conversely, someone within the healthy range might still carry more visceral fat — the harmful fat stored around internal organs — than is ideal. For this reason, the NHS recommends pairing your healthy weight result with a waist circumference check: over 94cm (37") for men or 80cm (31.5") for women is associated with increased health risk, regardless of BMI.
Despite these limitations, a healthy weight calculator remains one of the fastest, free, and most widely validated ways to get a sense of where you stand — and it gives you a concrete number to discuss with your GP if needed.
Healthy Weight for Men vs Women
The NHS applies the same healthy BMI band — 18.5 to 24.9 — to both men and women, so the healthy weight range calculation itself doesn't change based on gender. What does differ is typical body composition: women naturally carry a higher percentage of body fat than men at an equivalent BMI, largely due to hormonal and reproductive biology.
This means two people of the same height and weight, one male and one female, can have identical BMI results yet different underlying body fat percentages. It's one of the reasons many clinicians recommend using waist circumference or waist-to-hip ratio alongside your healthy weight range, particularly for women, to build a fuller picture of health risk.
Healthy Pregnancy Weight Gain Calculator
Pregnancy is one situation where standard healthy weight ranges do not apply — weight gain during pregnancy is expected and necessary for a healthy baby. Rather than aiming to stay within your pre-pregnancy healthy weight range, the relevant question becomes: how much weight gain is considered healthy over the course of pregnancy?
The NHS does not publish a single official UK target, but the following ranges are commonly used by midwives and are based on your BMI before becoming pregnant:
| Pre-Pregnancy BMI | Category | Typical Healthy Weight Gain |
|---|---|---|
| Below 18.5 | Underweight | 12.5 – 18 kg |
| 18.5 – 24.9 | Healthy weight | 11.5 – 16 kg |
| 25 – 29.9 | Overweight | 7 – 11.5 kg |
| 30 and above | Obese | 5 – 9 kg |
These figures are general guidance rather than fixed rules — your midwife or obstetrician will monitor your individual weight gain pattern throughout your pregnancy and advise you directly, since needs vary depending on factors such as multiple pregnancy, existing health conditions, and how the pregnancy is progressing.
Do not use this calculator to set weight-loss goals during pregnancy. Standard healthy weight ranges are designed for non-pregnant adults. Always follow guidance from your midwife or GP for weight management before, during, and after pregnancy.
How to Reach Your Healthy Weight
If you're below your healthy weight range: Speak to your GP. Being underweight can stem from many causes, including nutritional deficiencies, an underlying health condition, or disordered eating, and your GP can refer you to appropriate support.
If you're within your healthy weight range: Focus on maintaining it through a balanced diet and at least 150 minutes of moderate aerobic activity per week, as recommended by the NHS. Staying within range doesn't mean you can skip regular health checks.
If you're above your healthy weight range: Even modest weight loss of 5–10% of your current body weight can meaningfully reduce health risks. The NHS Better Health campaign offers a free 12-week weight loss plan, healthy recipes, and a tracking app to help you move steadily toward your healthy range.
If you're well above your healthy weight range: Speak to your GP for a full health assessment. They can refer you to NHS Tier 2 or Tier 3 weight management services, which include dietitian-led support, and in some cases prescription options such as Orlistat or Wegovy where clinically appropriate.
A healthy weight range is a helpful target, not a verdict on your worth. Weight is shaped by genetics, environment, mental health, and circumstance — approach any changes with patience, and don't hesitate to ask your GP for support along the way.