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
BMI Average Range — What's Healthy?
The average BMI in the UK is around 27.6 for adults, which falls in the overweight category according to NHS guidelines. However, a healthy BMI for most adults is between 18.5 and 24.9, regardless of the national average. Understanding your BMI range and where you fall within the NHS bmi categories uk helps you assess your weight-related health risk, though BMI is just one of several health indicators worth considering.
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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.
Understanding BMI Ranges and NHS Categories
The BMI formula divides your weight in kilograms by your height in metres squared (kg ÷ m²). The resulting number places you in one of five NHS categories:
- Underweight: BMI below 18.5 — may need medical assessment
- Healthy weight: BMI 18.5 to 24.9 — lowest health risk
- Overweight: BMI 25.0 to 29.9 — increased health risk
- Obese (Class I): BMI 30.0 to 34.9 — significant health risk
- Obese (Class II): BMI 35.0 to 39.9 — higher health risk
- Severely obese (Class III): BMI 40.0+ — substantial health risk
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a lower healthy BMI threshold of 18.5 to 22.9, as these populations face higher cardiovascular and diabetes risk at lower BMI levels. Use our free BMI calculator above to find your personal BMI instantly.
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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 BMI Average Range Matters Less Than Your Personal Health
The fact that the UK average BMI is around 27.6 doesn't mean this is healthy — it reflects that many adults are overweight. Your individual BMI matters more than the average. The overweight bmi threshold of 25.0 exists because medical evidence shows increased disease risk above this point, regardless of what others weigh.
BMI has real limitations: it doesn't distinguish muscle from fat, doesn't account for where fat is stored (waist measurement is important too), and may be less accurate for elderly adults or athletes. Your GP can help you understand what your BMI means for your specific health alongside other measurements like blood pressure, cholesterol, and waist circumference.
- 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's the average BMI in the UK?
The average BMI for UK adults is approximately 27.6, which falls in the overweight category. However, the average is not the same as healthy. NHS guidelines define a healthy BMI as 18.5 to 24.9 for most adults, lower for South Asian and Black populations at 18.5 to 22.9.
Is a BMI of 27 considered overweight?
Yes. According to NHS bmi range uk guidelines, a BMI of 27 falls in the overweight category (25.0 to 29.9). While not yet in the obese range, this BMI is associated with increased health risks compared to the healthy range of 18.5 to 24.9.
What healthy BMI should I aim for?
The healthy BMI range is 18.5 to 24.9 for most UK adults. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, aim for 18.5 to 22.9. Your exact healthy weight depends on your height — use the BMI calculator on this page to find your personal target range.
Why are there different BMI ranges for different ethnic groups?
Medical research shows that people of South Asian, Chinese, Black African, and Black Caribbean heritage develop weight-related health conditions (diabetes, heart disease) at lower BMI levels. The NHS adjusted these thresholds downward to better reflect actual health risk in these populations.
Does a high average BMI mean mine is acceptable?
No. Individual health risk is based on your personal BMI, not the national average. Even if many UK adults are overweight, a BMI below 25 remains the evidence-based healthy target for most people. Your GP can advise on what's appropriate for your specific circumstances.
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.