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
Free tracker included with every download this week
What is the Average BMI in the UK?
The average BMI in the UK has risen significantly over recent decades. According to the Office for National Statistics (ONS), the average BMI for UK adults is approximately 27.6 — putting the population just into the overweight category. Men average 27.9, women average 27.4. This means most UK adults fall above the NHS healthy BMI range of 18.5–24.9. Understanding where you sit relative to this data helps contextualise your personal BMI and health risk. Use our free BMI calculator above to check your individual BMI instantly.
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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.
Average UK BMI by Age, Sex and Region
National figures (ONS data): The average BMI for UK adults is approximately 27.6, with men averaging 27.9 and women 27.4. This places the average UK adult in the overweight BMI category according to NHS guidelines.
Age variation: BMI tends to increase with age, peaking in the 55–64 age group before declining slightly in older adults. Younger adults (18–24) typically have lower average BMI than those aged 35–54.
Regional differences: BMI varies across UK regions. Areas with higher rates of physical inactivity and lower access to healthy food options tend to show higher average BMI figures.
Health context: An average BMI of 27.6 correlates with increased risk of type 2 diabetes, cardiovascular disease, and certain cancers — which is why NHS weight management services emphasise bringing population averages down to the healthy range of 18.5–24.9.
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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.
Why Average BMI Doesn't Tell the Whole Story
While average BMI provides useful population context, BMI limitations are important to understand. BMI does not distinguish between muscle and fat — athletes and people with high muscle mass may have a high BMI but low body fat and excellent health. BMI also ignores where fat is stored; central obesity (excess fat around the stomach) carries greater health risk than fat distributed elsewhere.
The bmi formula (weight in kg ÷ height in metres squared) gives a useful screening tool, but your personal health risk depends on multiple factors: family history, fitness level, blood pressure, cholesterol, and blood sugar. Use our free weight converter to track your weight in the units you prefer, and discuss your individual health context with your GP rather than comparing yourself only to the population average.
- 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.
How does my BMI compare to the average UK BMI?
The average UK BMI is 27.6 — in the overweight category. If your BMI is under 25, you're below the UK average. If it's 25–29.9, you're at average or slightly below. Over 30, you're above average. However, individual health depends on many factors beyond BMI alone, so discuss your personal context with your GP.
What is the healthy BMI range according to NHS guidelines?
The NHS healthy BMI range is 18.5–24.9 for most adults. People of South Asian, Chinese, Black African, or Black Caribbean heritage should aim for 18.5–22.9 due to higher health risk at the same BMI. Calculate your personal healthy weight range using our free BMI calculator.
Why has average UK BMI increased over time?
UK average BMI has risen due to increased sedentary behaviour, changes in food availability and portion sizes, reduced physical activity in daily life, and increased stress and sleep disruption. Public Health England recognises obesity as a significant population health challenge requiring multi-level intervention.
Is the average UK BMI the same for men and women?
No. The average BMI for UK men is 27.9, while for women it's 27.4. Both are above the healthy BMI range. Women tend to have slightly lower average BMI than men, though both populations show high rates of overweight and obesity.
What should I do if my BMI is above the average UK BMI?
Even if your BMI is close to the UK average, being in the overweight or obese category carries health risks. Discuss your personal context with your GP. Small changes — such as increased activity, reduced calorie intake, or structured weight management — can significantly improve health outcomes. Our GLP-1 weight loss calculator can help you explore potential options.
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.