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 Range in the UK?
The average BMI in the UK is around 27.4 for adults, which falls into the overweight category according to NHS guidelines. However, a healthy BMI range is 18.5 to 24.9 regardless of what the population average is. Understanding the difference between average BMI and healthy BMI is important for your personal health. Use our free BMI calculator above to find out where your individual BMI sits and what that means for your health.
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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.
NHS BMI Categories and Healthy Ranges Explained
The NHS defines five BMI categories for adults, and these are used across UK healthcare services:
- Underweight: BMI below 18.5
- Healthy weight: BMI 18.5 to 24.9 (this is the target range)
- Overweight: BMI 25.0 to 29.9
- Obese (Class I): BMI 30.0 to 34.9
- Obese (Class II): BMI 35.0 to 39.9
- Severely obese (Class III): BMI 40.0 and above
The bmi formula is simple: weight in kilograms divided by height in metres squared. Knowing which bmi range uk you fall into helps your GP assess health risks. The healthy BMI threshold is the same for all adults, though some groups face higher health risks at lower BMI levels (see Section 3). According to recent data, around 63% of UK adults are classified as overweight or obese, meaning most fall outside the healthy range.
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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 Has Limitations and What Else Matters
BMI is a useful screening tool but has important limitations. It does not distinguish between muscle and fat—so athletes with significant muscle mass may have a high BMI despite low body fat. BMI also does not account for where fat is stored on your body. Waist circumference is equally important: for men, over 94cm indicates increased health risk; over 102cm indicates high risk. For women, the thresholds are 80cm and 88cm respectively. Your GP can assess your overall health risk by considering BMI alongside other factors including blood pressure, cholesterol, and waist measurement. Our free weight converter can help you check your weight in different units to monitor changes over time.
- 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.
Is an average BMI of 27 considered healthy?
No. A BMI of 27 falls into the overweight category (25.0–29.9). Whilst it's close to the healthy range, the NHS recommends aiming for a BMI between 18.5 and 24.9 for optimal health. Even moving from 27 to 25 can reduce health risks.
Why is the average UK BMI higher than the healthy range?
The UK average (around 27.4) reflects that many adults are overweight or obese. This is largely due to changes in diet, activity levels, and lifestyle factors over recent decades. The average being higher doesn't make it healthy—it indicates a population-level health challenge.
Do I need to reach the lower end of the healthy BMI range?
Not necessarily. Any BMI within the healthy range (18.5–24.9) is considered good. Your target depends on factors like age, genetics, muscle mass, and existing health conditions. Your GP can advise on a realistic target for you personally.
What if I'm from a South Asian or Black African background—are the BMI categories different?
Yes. The NHS recommends lower thresholds for people of South Asian, Chinese, Black African, and Black Caribbean heritage because these groups face higher cardiovascular and diabetes risk at lower BMI levels. For these groups, healthy BMI is 18.5–22.9, and overweight starts at 23.0.
How can I calculate whether my weight is in the healthy BMI range for my height?
Use our free BMI calculator on this page—it instantly shows your BMI and category. Alternatively, use the bmi calculator formula: weight (kg) ÷ height (m)². For example, at 1.73m tall, a healthy weight range is approximately 55–74kg (8st 10lbs to 11st 10lbs).
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.