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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Understanding the Obese Chart in the UK
An obese chart shows BMI ranges that indicate excess weight affecting health. In the UK, obesity is defined as a BMI of 30 or above, with further classifications for more severe obesity. This guide explains what these categories mean for your health, the conditions linked to excess weight, and the support available through the NHS and other services. Whether you're checking where you stand or exploring next steps, understanding the obese chart is an important first part of taking control of your health.
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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.
Health Conditions Linked to Excess Weight
Excess weight increases the risk of several serious health conditions. Type 2 diabetes is among the most common — obesity increases diabetes risk by up to 80 times compared to healthy weight. Cardiovascular disease, including heart attack and stroke, is significantly more common in obese adults. High blood pressure, abnormal cholesterol levels, and obstructive sleep apnoea are also closely linked to obesity.
Other conditions associated with excess weight include osteoarthritis, certain cancers (linked to 13 different cancer types), and non-alcoholic fatty liver disease. Where fat is stored also matters — excess weight around the waist carries particular health risks. Use our free BMI calculator above to check your personal BMI, and measure your waist circumference: a healthy waist measurement is below 94cm (37 inches) for men and 80cm (31.5 inches) for women.
Even modest weight loss — as little as 5–10% of your current weight — can significantly reduce these health risks and improve markers like blood pressure and blood sugar 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.
Support and Next Steps for Managing Weight
If your obese BMI indicates excess weight, several support options are available. The NHS offers weight management services across four tiers: tier 1 includes digital tools and community programmes; tier 2 involves primary care support; tier 3 provides specialist multidisciplinary services where prescription weight loss medication may be prescribed; and tier 4 covers bariatric surgery for severe obesity.
Speak to your GP about accessing weight management support in your area. For adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, prescription weight loss treatments may be available following clinical assessment. These are used alongside dietary changes and increased physical activity — not instead of them. Our GLP-1 weight loss calculator can help you estimate potential outcomes if eligible. Track your progress using our free progress tracker as you work towards a healthier weight.
- 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 BMI counts as obese on a UK chart?
According to NHS guidelines, a BMI of 30 or above is classified as obese. This is further divided into Class I obesity (30–34.9), Class II obesity (35–39.9), and Class III or severe obesity (40 and above). For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds starting at BMI 27.5.
How is the obese chart different from an overweight chart?
The overweight BMI category is 25–29.9, while obesity starts at 30. An "obese bmi uk" chart shows three obesity classifications based on increasing health risks. The higher your BMI within the obese range, the greater the health risks. Calculate your personal BMI using our free calculator to see exactly where you fall.
Am I overweight or obese?
If your BMI is between 25–29.9, you're classified as overweight. If your BMI is 30 or above, you're in the obese category. Your "healthy weight range" depends on your height — use our weight converter and BMI calculator to find out where your personal healthy range sits. Your GP can also help assess your individual risk factors.
What health risks come with an obese BMI?
Obesity is linked to type 2 diabetes, heart disease, stroke, high blood pressure, sleep apnoea, and certain cancers. Risk also depends on "waist measurement health risk" — excess belly fat carries particular risk. Men should aim for a waist below 94cm, women below 80cm. Even 5–clinically studied weight loss reduces these risks significantly.
What support is available if I have an obese BMI?
Your GP can refer you to NHS weight management services (tier 2 or 3), which may include behaviour change programmes and prescription weight loss medication. Private options are also available following clinical assessment. Medication is used alongside diet and exercise. Ask your GP about accessing "weight check nhs" services in your area, or explore prescription options if eligible.
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.