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 According to NHS Guidelines?
The average BMI range for UK adults falls between 18.5 and 24.9, which the NHS classifies as a healthy weight. However, most UK adults are currently overweight or obese, with an average BMI above the healthy threshold. Understanding your personal BMI range and how it compares to NHS recommendations is the first step toward managing your health. Use our free BMI calculator above to discover your individual BMI instantly and see where you fall within the NHS categories.
10,000+ calculations today ยท NHS-aligned thresholds ยท 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/mยฒ).
While BMI isn't a perfect measure โ it doesn't account for muscle mass, bone density, or fat distribution โ 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 โ 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 Weight Standards
The NHS uses five official BMI categories to classify adults based on their weight and height. A healthy BMI range of 18.5 to 24.9 is the target recommended by the NHS and aligns with evidence-based health outcomes. However, UK statistics show that approximately 63% of adults are overweight or obese, with an average BMI above 27. The BMI formula used by the NHS is straightforward: weight in kilograms divided by height in metres squared. For a typical UK adult, a healthy BMI range means different weights depending on height. For example, at 5ft 8in (173cm), a healthy BMI falls between approximately 55โ74kg (8st 9lbsโ11st 8lbs).
- BMI below 18.5: Underweight
- BMI 18.5โ24.9: Healthy weight (NHS target)
- BMI 25.0โ29.9: Overweight
- BMI 30.0โ34.9: Obese (Class I)
- BMI 35.0+: Severely obese
Important: BMI limitations exist โ it does not distinguish between muscle and fat, nor account for where fat is stored around the body.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care โ 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 โ 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 โ completely free.
NHS Guidance, Support, and When to Seek Help
The NHS recommends that if your BMI falls outside the healthy range (18.5โ24.9), you should consider speaking with your GP. The NHS offers a structured weight management pathway with support at different tiers: self-help resources and digital tools at tier 1, primary care-based programmes at tier 2, specialist multidisciplinary services at tier 3, and bariatric surgery assessment at tier 4. Your GP can assess whether your weight poses health risks and signpost you to appropriate support. The NHS also emphasises that losing even 5โ10% of body weight can improve blood pressure, blood sugar control, and reduce health risks significantly.
- Waist circumference matters alongside BMI โ men over 102cm and women over 88cm face increased risk
- For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply
- The progress tracker on this page helps log weight 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 โ 5mg โ 7.5mg โ 10mg โ 12.5mg โ 15mg
- GLP-1 receptor agonist
- Up to 15โ17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg โ 0.5mg โ 1mg โ 1.7mg โ 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 | 15โ22.5% | 12โ17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20โ32 weeks | 16โ20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | ยฃ150โยฃ250/month | ยฃ150โยฃ300/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 โ 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 a normal BMI range according to the NHS?
The NHS defines a healthy BMI range as 18.5 to 24.9 for adults. This range is evidence-based and associated with lower health risks. However, for adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a lower range of 18.5 to 22.9 due to higher risk thresholds in these populations.
What is the average BMI of UK adults?
The average BMI of UK adults is approximately 27โ28, which falls in the overweight category. Around 63% of UK adults are overweight or obese (BMI 25+), and 28% meet the definition of obese (BMI 30+). This means the average UK adult BMI is above the NHS healthy weight target.
Does my BMI need to be exactly in the healthy range?
Your BMI does not need to be perfectly centred within the healthy range โ anywhere between 18.5 and 24.9 is considered healthy by NHS standards. The BMI range allows for natural variation based on body composition, frame size, and muscle mass. Your GP can discuss your individual circumstances.
What should I do if my BMI is above the NHS healthy range?
If your BMI exceeds 24.9, speak with your GP. They can assess your overall health, including waist circumference and any weight-related health conditions. The NHS offers tier 1 resources (including digital tools like our weight converter and BMI calculator), tier 2 programmes, and tier 3 specialist services depending on your BMI and health needs.
Why do ethnicity adjustments exist in BMI categories?
Research shows that people of South Asian, Chinese, Black African, and Black Caribbean heritage develop weight-related health conditions (particularly type 2 diabetes and cardiovascular disease) at lower BMI levels than Europeans. The NHS therefore recommends adjusted thresholds for these groups to ensure earlier intervention and appropriate health protection.
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.