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
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BMI Score Chart — Understanding Your Health Range
A BMI score chart shows where your weight falls according to NHS health guidelines. Your BMI (body mass index) is calculated from your height and weight, and the chart categorises it into ranges that indicate whether you're at a healthy weight or whether your health might benefit from changes. This guide explains the chart, what your score means, and how to use it with other health measures. Use our free BMI calculator above to find your personal score instantly.
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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 Score Categories and What They Mean
The NHS BMI formula divides your weight in kilograms by your height in metres squared. According to NHS guidelines, the healthy BMI range is 18.5 to 24.9 for most UK adults. Here's the complete BMI chart UK breakdown:
- Below 18.5: Underweight — may indicate insufficient calorie intake or underlying health issues
- 18.5–24.9: Healthy weight — associated with lower risk of weight-related diseases
- 25.0–29.9: Overweight — overweight BMI threshold begins here; increased health risk
- 30.0–34.9: Obese (Class I) — significantly elevated health risks
- 35.0–39.9: Obese (Class II) — higher disease risk
- 40.0+: Severely obese (Class III) — serious health concerns
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower bmi categories uk thresholds, with healthy weight starting at 18.5 and overweight beginning at 23.0, as these groups face higher cardiovascular risk at lower BMI levels.
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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.
BMI Limitations and What Else Matters for Health
While the BMI calculator is a useful screening tool, it has important limitations. BMI limitations include that it doesn't distinguish between muscle and fat — athletes or people with high muscle mass may have a high score despite low body fat. BMI also ignores where fat is stored; central fat around the stomach poses greater health risks than fat elsewhere. Age, bone density, and ethnicity all affect what a healthy BMI means for you personally.
Alongside your BMI score, measure your waist circumference: men should aim for under 94cm (37 inches), women under 80cm (31.5 inches). Combining your BMI with waist measurement and blood pressure checks gives a much clearer picture of your health risk. Your GP can assess your individual circumstances and recommend next steps if needed.
- 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 is a good BMI score?
A good BMI score falls between 18.5 and 24.9 according to NHS guidelines. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, a healthy score is 18.5 to 22.9. Your GP can advise what's healthy for your individual circumstances, as age, muscle mass, and medical history all matter.
What BMI number is considered obese?
A BMI of 30.0 or above is classified as obese according to NHS categories. Class I obesity is 30.0–34.9, Class II is 35.0–39.9, and Class III (severe obesity) is 40.0 and above. These are screening categories only — your GP provides personalised health assessment.
How accurate is a BMI chart?
BMI charts are useful screening tools but have limitations. They don't account for muscle mass, so athletes may have high BMI with low body fat. They also ignore where fat is stored and don't reflect individual health factors like age or fitness level. Use BMI alongside waist measurement and GP advice for a fuller picture.
What healthy BMI range should I aim for?
The NHS healthy BMI range is 18.5 to 24.9 for most UK adults. For South Asian, Chinese, Black African, and Black Caribbean adults, aim for 18.5 to 22.9. Calculate your personal healthy weight range using our free BMI calculator above, or speak to your GP about targets suited to your health.
Can I have a high BMI but still be healthy?
In some cases, yes — athletes with significant muscle mass can have higher BMI with low body fat. However, for most people, BMI above 25 is associated with increased health risk. Your GP can assess your individual health using BMI alongside blood pressure, cholesterol, fitness level, and family history for a complete picture.
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.