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 UK adults is approximately 27.4 for women and 27.9 for men — both in the overweight category according to NHS guidelines. These figures reflect decades of health trend data from the Office for National Statistics. While average doesn't mean healthy, understanding where your BMI sits relative to NHS recommendations and the broader UK population can help you assess your personal health risk. Our free BMI calculator above can show you how your individual BMI compares to these national averages and NHS healthy weight ranges.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
NHS BMI Categories and UK Health Standards
The NHS classifies BMI into five categories that apply to all UK adults:
- Underweight: below 18.5
- Healthy weight: 18.5 to 24.9
- Overweight: 25.0 to 29.9
- Obese (Class I): 30.0 to 34.9
- Obese (Class II–III): 35.0 and above
Because the average UK adult BMI falls into the overweight range, many people are at increased risk of weight-related health conditions including type 2 diabetes, cardiovascular disease, and high blood pressure. NICE guidance emphasises that BMI is a useful screening tool, though it has limitations — it doesn't distinguish between muscle and fat, and doesn't account for where fat is stored. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds: healthy weight is 18.5 to 22.9, and overweight begins at 23.0. Use the BMI range UK reference above to see where the average fits, or calculate your personal BMI now.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
NHS Weight Management Support and When to Seek Help
The NHS offers a structured weight management pathway designed to support people at every stage. Tier 1 focuses on self-help and community programmes; Tier 2 involves primary care interventions like behaviour change support through your GP; Tier 3 provides specialist multidisciplinary weight management services where prescription medications may be offered; Tier 4 covers bariatric surgery for severe obesity with significant health complications. Because the average UK adult is overweight or obese, the NHS encourages anyone concerned about their weight to start by speaking with their GP. Even a modest 5–10% reduction in body weight can improve blood pressure, blood sugar control, and overall health outcomes.
- 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.
Why is the average BMI in the UK so high?
Multiple factors contribute: increased portion sizes, more sedentary work, higher consumption of ultra-processed foods, and reduced physical activity. Socioeconomic factors, access to healthy food, and health conditions like PCOS and thyroid disorders also play a role. It's not simply about individual choices — environmental and systemic factors matter significantly.
Is my BMI unhealthy if it matches the UK average?
Not necessarily. While the average is in the overweight category, individual health depends on many factors: muscle mass, where fat is stored (waist circumference matters), fitness level, blood pressure, and blood sugar control. Your GP can assess your personal health risk using BMI alongside other measurements and your medical history.
How does the BMI limitations affect understanding the UK average?
The BMI formula doesn't distinguish muscle from fat, so athletes and very muscular individuals may have high BMI despite low body fat. It also ignores distribution of fat — excess belly fat poses greater health risk than fat stored elsewhere. The bmi formula is useful as a screening tool but shouldn't be your only health metric.
What does NHS recommend for a healthy BMI?
The NHS recommends a healthy BMI of 18.5 to 24.9 for most UK adults. This range is associated with the lowest health risks. However, for South Asian and certain other ethnicities, lower thresholds apply due to higher cardiovascular risk at standard BMI levels. Your GP can advise what's healthy for you personally.
How can I check if my BMI is healthy?
Use our free BMI calculator on this page to find your personal BMI instantly, or calculate using the bmi formula: weight (kg) divided by height (m) squared. The result shows which NHS category you fall into. Our weight converter also helps if you need to switch between stone, pounds, and kilograms first.
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.