The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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What Is Your Ideal Weight? UK Health Guide
Your ideal weight depends on your height, age, muscle mass, and overall health rather than a single target number. According to NHS guidelines, a healthy weight range for adults is defined by a BMI of 18.5 to 24.9, though this varies by ethnicity. The average UK adult man weighs approximately 85.7 kg (13st 7lbs) and the average woman weighs 71.6 kg (11st 3lbs). However, "ideal" is personal and influenced by genetics, frame size, and medical history. Use our free BMI calculator above to find your healthy weight range for your specific height.
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Calculate Your BMI Instantly
Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
Healthy Weight Ranges by Height — UK Data
Rather than a single ideal weight, the NHS recommends a healthy weight range based on height and BMI. For most adults, a BMI of 18.5 to 24.9 is considered healthy.
- 5ft 4in (163cm): healthy weight range is approximately 47–63 kg (7st 5lbs to 9st 12lbs)
- 5ft 8in (173cm): healthy weight range is approximately 55–75 kg (8st 9lbs to 11st 11lbs)
- 5ft 10in (178cm): healthy weight range is approximately 58–79 kg (9st 2lbs to 12st 6lbs)
- 6ft 0in (183cm): healthy weight range is approximately 61–83 kg (9st 8lbs to 13st 1lbs)
These ranges apply to most adults of White European heritage. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds (18.5–22.9 for healthy weight) due to higher health risks at standard BMI levels. Calculate your personal healthy weight range instantly using the BMI calculator on this page.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Factors That Influence Your Ideal Weight
Your ideal weight is not fixed — it depends on multiple factors beyond height. Muscle mass significantly affects your weight; muscle is denser than fat, so two people of identical height and BMI can weigh differently. Frame size (small, medium, large bone structure) also matters — people with larger frames may have higher healthy weights. Age influences ideal weight as muscle naturally decreases with age. Genetics play a role; some people are naturally heavier or lighter. Ethnicity affects health risk at different BMI levels. Medical conditions, medications, and hormonal factors also impact your ideal weight. Your GP can provide personalised guidance on what's healthy for you specifically, rather than aiming for a generic "ideal" number.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
What is the ideal weight for a 5ft 8in adult?
For an adult 5ft 8in (173cm) tall, the healthy weight range according to NHS guidelines is approximately 55–75 kg (8st 9lbs to 11st 11lbs), based on a BMI of 18.5 to 24.9. However, ideal weight varies by age, muscle mass, and frame size. Use our BMI calculator above to find your specific healthy range.
Is there a difference between ideal weight and healthy weight?
Yes. "Healthy weight" is defined by BMI ranges (18.5–24.9) and is based on population health data. "Ideal weight" is more personal and accounts for individual factors like muscle mass, frame size, age, and genetics. A healthy BMI range is a useful starting point, but your personal ideal weight may vary within or around that range.
What is the average weight of a UK adult?
According to ONS (Office for National Statistics) data, the average UK adult man weighs approximately 85.7 kg (13st 7lbs) at a height of 175.3 cm (5ft 9in), giving an average BMI of 27.9. The average UK adult woman weighs approximately 71.6 kg (11st 3lbs) at 161.6 cm (5ft 3.5in), with an average BMI of 27.4. Both averages fall into the overweight category.
Do ethnicity-adjusted weight guidelines exist in the UK?
Yes. The NHS recommends lower BMI thresholds for adults of South Asian, Chinese, Black African, and Black Caribbean heritage: a healthy BMI is 18.5–22.9 rather than 18.5–24.9. This is because these groups face higher risks of type 2 diabetes and cardiovascular disease at standard BMI levels. Your GP can discuss what's appropriate for your background.
How do I calculate my ideal weight for my height?
Use the free BMI calculator on this page to find your healthy weight range based on your height. Multiply your height in metres by itself, then divide your weight in kg by that number. A result of 18.5–24.9 is considered healthy. For a more personalised approach, discuss your ideal weight with your GP, as it depends on factors beyond BMI like muscle mass and frame size.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.