🎯 NHS-Informed · Healthy Weight Guide · Updated July 2026
Ideal Weight Calculator UK — What Should I Weigh?
Find your ideal weight range, NHS healthy weight range, and BMI reference in seconds — using your height, sex and age. Free, no sign-up, NHS-aligned.
📅 Last Updated: July 2026🩺 NHS BMI Standards✅ Fact Checked🆓 Free · No Sign-Up
18.5–24.9
NHS Healthy BMI
21.7
Mid-Range Reference BMI
3
Formula Methods Used
Free
Always Free
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Written byBMI Calculator NHS Editorial TeamHealth & Weight Management Writers specialising in NHS BMI guidance and healthy weight standards for UK adults
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Medically ReviewedNHS-Aligned Health Review PanelContent reviewed against NHS Live Well, NICE weight management guidelines, and NICE Obesity QS111 · July 2026
What Is an Ideal Weight Calculator UK?
An ideal weight calculator UK estimates a realistic, healthy target weight for your height, sex and age using NHS BMI guidance and classic body weight formulas. It answers one of the most common health questions — what should I weigh UK? — with a clear, practical range rather than a single arbitrary number.
There is no single "perfect" body weight. Most adults have a healthy weight range — a band of weights that are all consistent with good health — rather than one magic figure. This healthy weight calculator shows you both your broader NHS-based healthy weight range (all weights within BMI 18.5–24.9) and a narrower ideal target band, so you have a realistic goal for everyday planning.
To check your current BMI before using this tool, visit our BMI Calculator NHS. To see what different BMI values look like visually, try our visual BMI calculator.
How This Ideal Weight Calculator Works
This average weight calculator UK uses three well-established methods and blends the results:
NHS BMI Formula: Healthy weight range = BMI 18.5–24.9 × height(m)². This is the primary NHS standard used by GPs across the UK.
Hamwi Formula: A classic sex-specific formula widely used in clinical dietetics — 48 kg (women) or 52 kg (men) for the first 152 cm of height, plus 2.7 kg per additional inch (women) or 2.9 kg per inch (men).
Devine Formula: Developed for medication dosing, now used as an ideal body weight reference — 45.5 kg (women) or 50 kg (men) for 152 cm, plus 2.3 kg per additional inch above.
The calculator presents the NHS BMI range as your healthy weight range and the midpoint of the Hamwi/Devine results as your ideal target range. The BMI 21.7 midpoint is used as the central ideal reference — it sits comfortably within the NHS healthy range and reflects a sustainable, realistic target for most UK adults.
NHS Guidance: A BMI between 18.5 and 24.9 is classified as a healthy weight for most UK adults. Any weight within this range is medically appropriate — there is no single "best" weight within the healthy band. For adults of South Asian, Chinese or Japanese ethnicity, the NHS recommends lower thresholds: healthy below BMI 23, increased risk at 23–27.4, high risk at 27.5+.
What the NHS Says About Ideal Weight
The NHS does not officially promote a single "ideal weight." Instead, NHS guidance focuses on the healthy BMI range of 18.5 to 24.9 and encourages adults to aim for any weight within this band. The NHS Live Well weight management programme, NICE guidelines CG43 and QS111, and PHE healthy weight guidance all use this same BMI range as the core standard.
For weight management planning, the NHS recommends gradual, sustainable weight loss of 0.5–1 kg per week for those who are overweight or obese. This is typically achieved through a moderate calorie deficit of 500–1,000 kcal per day, combined with regular physical activity. Our NHS weight loss calculator can help you plan a timeline for reaching your ideal weight, and our calorie deficit calculator NHS will give you your exact daily calorie target.
NHS Ideal Weight Reference Table by Height
The table below shows the NHS healthy weight range and midpoint ideal weight for common UK adult heights, for both men and women:
Height
Min Healthy (kg)
Ideal Midpoint (kg)
Max Healthy (kg)
Min (st/lb)
Max (st/lb)
155 cm (5'1")
44.4
52.0
59.8
6st 13lb
9st 6lb
160 cm (5'3")
47.4
55.5
63.7
7st 7lb
10st 0lb
163 cm (5'4")
49.2
57.7
66.2
7st 10lb
10st 6lb
168 cm (5'6")
52.3
61.3
70.3
8st 3lb
11st 1lb
170 cm (5'7")
53.5
62.7
71.9
8st 6lb
11st 5lb
173 cm (5'8")
55.4
65.0
74.5
8st 10lb
11st 10lb
178 cm (5'10")
58.7
68.8
79.0
9st 3lb
12st 6lb
183 cm (6'0")
61.9
72.7
83.4
9st 11lb
13st 2lb
188 cm (6'2")
65.3
76.6
87.9
10st 4lb
13st 12lb
These ranges apply to most UK adults regardless of sex — the NHS uses the same BMI thresholds for men and women. For your personalised figure, use the calculator on this page. For a complete chart covering every height from 150–200 cm, see our healthy weight range by height guide.
Average UK Adult Weight vs Ideal Weight — What's the Difference?
One of the most important — and most overlooked — distinctions in weight management is the difference between the average weight of UK adults and the ideal or healthy weight for a given height. These two figures are not the same, and confusing them can lead to false reassurance or missed health opportunities.
What Is the Average Weight of a UK Adult?
According to NHS Digital's Health Survey for England, the average adult weight in England is approximately 83.9 kg for men and 70.2 kg for women. However, the average UK adult is overweight by NHS BMI standards. Approximately 64% of adults in England are overweight or obese. This means that if you aim to weigh what the "average" UK adult weighs, you are likely aiming for a weight that carries increased health risk.
The ideal weight produced by this calculator is based on the NHS healthy BMI range — not on population averages. Aiming for your ideal weight rather than the national average is a meaningful and clinically evidence-based goal. For a personalised weight loss timeline, use our weight loss timeline calculator or our target weight date calculator.
Why Ideal Weight Is a Range, Not a Number
Even within the NHS healthy BMI range (18.5–24.9), there is significant natural variation in what constitutes a healthy weight for any individual. Two adults of the same height may both be in excellent health — one at the lower end of the range (BMI 19), one at the upper end (BMI 24). The difference is often explained by:
Bone density: Denser bones weigh more. Adults with larger skeletal frames may naturally sit at the higher end of the healthy range.
Muscle mass: Lean muscle weighs more than fat. Regular exercisers often maintain higher body weights within the healthy range while carrying very low body fat.
Body fat distribution: Where fat is stored (hips and thighs vs abdomen) affects health risk independently of total weight. Waist circumference is often a more sensitive health indicator than weight alone.
Age: Metabolic rate naturally decreases with age. Some research suggests that adults over 65 may benefit from a slightly higher BMI (up to 27) as a reserve against illness and frailty.
📋 Key Facts — Ideal Weight Calculator UK
⚖️NHS healthy BMI: 18.5–24.9 for most UK adults
🎯Mid-range ideal BMI: approximately 21.7 (used as central reference)
📊UK average BMI: approximately 27.4 — overweight by NHS standards
🏋️Muscle mass: Can increase weight within healthy BMI range — use body fat % alongside BMI
👴Over 65: NHS guidance allows up to BMI 27 as a healthy range in older adults
Once you have your ideal weight range from this calculator, the most productive approach is to use it as a planning guide rather than a rigid daily target. Here is how to act on the result:
If your current weight is within the healthy range — focus on consistency and maintenance. Monitor monthly rather than daily.
If your current weight is above the healthy range — set the upper limit of your healthy range as an intermediate target. Even a 5–10% reduction in current weight produces measurable health benefits. Plan your journey with our NHS weight loss calculator.
If your current weight is below the healthy range — focus on gradual, nutritious weight gain. See our healthy weight gain guide for NHS-aligned advice.
✅ Tip: Weigh yourself weekly rather than daily — at the same time of day, wearing similar clothing. Normal daily weight fluctuations of 1–2 kg due to water retention, food, and hormonal changes are entirely normal and should not trigger concern. The trend over 4–6 weeks is the meaningful signal.
BMI Limitations — When Ideal Weight Calculations Are Less Accurate
BMI-based ideal weight calculations are excellent screening tools for most adults but have known limitations for specific groups:
Very muscular adults: May weigh above the healthy range while having an excellent body fat percentage. Athletes and bodybuilders should use body fat percentage alongside BMI.
Older adults (65+): Ideal weight may be slightly higher due to natural muscle loss and the protective role of weight reserves during illness.
Pregnant or breastfeeding women: Standard ideal weight calculations do not apply during pregnancy.
People with eating disorders: This calculator is not appropriate for individuals with or recovering from an eating disorder. Please seek specialist support.
Very tall or very short individuals: BMI can be less accurate at height extremes. Waist circumference is a useful complementary measure.
For a fuller body composition picture alongside this ideal weight tool, explore our BMI vs body fat percentage guide and our general health weight ratios tool, which covers waist-to-height ratio and waist-to-hip ratio.
How to Reach and Maintain Your Ideal Weight — NHS Guidance
Knowing your ideal weight is the starting point. Reaching it — and staying there — requires a sustainable, evidence-based approach. The NHS and NICE both emphasise that gradual, steady weight change produces far better long-term outcomes than rapid dieting. Here is the NHS-aligned framework:
Safe Rate of Weight Change
The NHS recommends losing 0.5–1 kg per week for sustainable fat loss. This requires a daily calorie deficit of approximately 500–1,000 kcal. Faster rates of loss increase the risk of muscle mass reduction, nutritional deficiency, and weight regain. Read our safe rate of weight loss per week guide for the full evidence behind this recommendation.
Calorie Deficit for Weight Loss
To lose weight, you need to consume fewer calories than your body uses each day. The NHS does not recommend going below 1,200 kcal/day for women or 1,500 kcal/day for men without medical supervision. Our calorie deficit calculator NHS will calculate your exact maintenance calories and recommended deficit based on your measurements and activity level.
Physical Activity
The NHS recommends at least 150 minutes of moderate-intensity aerobic activity per week (such as brisk walking, cycling, or swimming), plus strength training at least twice weekly. Exercise contributes to the calorie deficit, preserves lean muscle during weight loss, and delivers cardiovascular benefits that diet alone cannot achieve.
Long-Term Weight Maintenance
Research consistently shows that weight maintenance is harder than weight loss for most people — primarily because metabolic rate decreases as body weight falls. Practical maintenance strategies include:
Weighing yourself weekly and acting on upward trends early (2–3 kg drift is much easier to address than 10 kg)
Maintaining the same dietary habits that produced the initial weight loss
Continuing or increasing physical activity — particularly resistance training
Using our BMI progress explained tool to track centile progress and celebrate milestones
⚠️ Medical Context Matters: Pregnancy, chronic illness, thyroid conditions, eating disorders, menopause, and high athletic muscle mass can all significantly affect how ideal weight should be interpreted. Always discuss your weight management goals with your GP, practice nurse, or a registered dietitian before starting a new diet or exercise programme.
Related Tools for Your Weight Journey
Use these free NHS-aligned tools alongside this ideal weight calculator to build a complete, actionable weight management plan:
Hamwi GJ (1964) — "Therapy: Changing dietary concepts." Diabetes Mellitus: Diagnosis and Treatment. American Diabetes Association.
Devine BJ (1974) — "Gentamicin therapy." Drug Intelligence and Clinical Pharmacy, 8, 650–655.
⚠️ Medical Disclaimer: This ideal weight calculator UK is for informational and educational purposes only. Results are estimates based on generalised formulas and do not constitute medical advice. BMI and ideal weight calculations have limitations — particularly for muscular individuals, older adults, and those with eating disorders or chronic illness. BMI Calculator NHS is not affiliated with NHS England, NICE, or any government body. Always consult your GP, practice nurse, or a registered dietitian before making significant changes to your diet or exercise habits. See our full Disclaimer, Privacy Policy, and Terms of Service.
Frequently Asked Questions — Ideal Weight Calculator UK
An ideal weight calculator UK estimates a sensible target weight based on your height, sex, and NHS BMI guidance. It gives a practical ideal weight range and a wider healthy weight range (BMI 18.5–24.9) rather than one single rigid number — because healthy weight is a range, not a fixed figure. This calculator uses a combination of the NHS BMI formula and classic Hamwi/Devine ideal weight formulas to give you both a broad healthy range and a narrower planning target.
The best starting point is your height and the NHS healthy BMI range of 18.5–24.9. Our ideal weight calculator UK converts this into your healthy weight range in kilograms and stones. It also adds a narrower ideal range. For your personalised weight loss plan, use our NHS weight loss calculator. For your daily calorie target, use our calorie deficit calculator NHS.
Not exactly. A healthy weight range (based on BMI 18.5–24.9) is broader — it covers all weights that are medically appropriate. An ideal weight range is a narrower planning target within that healthy band, typically centred around BMI 21–22. In practice, any weight within the NHS healthy range is appropriate. The ideal range simply gives you a more focused planning target if you want one.
Classic ideal weight formulas (Hamwi, Devine) use both height and sex because average body frame and lean mass differ between men and women at the same height. Men typically have more lean muscle mass per centimetre of height, resulting in a slightly higher ideal weight estimate than women of the same height. The NHS BMI healthy range itself uses the same thresholds for both sexes, but the ideal target band within that range is sex-adjusted.
Yes. Very muscular adults may weigh more than the calculator suggests while still being healthy — because muscle tissue is denser than fat. BMI and ideal-weight formulas do not directly measure body fat or muscle mass. If you exercise heavily or have a larger athletic build, use the result as a guide and consider waist circumference or body fat percentage alongside it. Our BMI vs body fat percentage guide explains this in detail.
This calculator uses two methods: the NHS BMI formula (BMI 18.5–24.9 × height m²) to produce the healthy weight range, and a combined Hamwi/Devine formula adjusted for UK population to produce the narrower ideal weight range. The BMI 21.7 midpoint serves as the central ideal reference. For more on how BMI is derived, see our BMI formula explained with examples guide.
According to NHS Digital data, the average adult weight in England is approximately 83.9 kg for men and 70.2 kg for women. However, the average UK adult is overweight by NHS BMI standards — approximately 64% of English adults are overweight or obese. Use this ideal weight calculator UK to find your personal healthy range rather than aiming for the national average. Check your current BMI with our BMI Calculator NHS.
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