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 Good BMI for Males in the UK?
A good BMI for adult males in the UK is between 18.5 and 24.9, according to NHS guidelines. This range is considered healthy weight for most men. However, your individual healthy weight depends on your height, and other factors like muscle mass and where fat is stored also matter. The NHS BMI calculator uses the standard BMI formula to assess whether your weight falls into a healthy range, but BMI is just one screening tool — it doesn't account for fitness level or body composition.
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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 Categories for Men
The NHS defines BMI categories for adult males as follows: a BMI below 18.5 is underweight, 18.5–24.9 is healthy weight, 25.0–29.9 is overweight, 30.0–34.9 is obese (Class I), 35.0–39.9 is obese (Class II), and 40.0 or above is severely obese (Class III). These categories are based on the standard BMI formula: weight (kg) divided by height (m) squared. For example, a man who is 1.78m (5ft 10in) tall would have a healthy BMI range of approximately 56–70 kg (8st 11lbs to 11st 0lbs). The NHS uses these categories to identify individuals who may benefit from lifestyle changes or further health assessment. NICE guidance recommends that BMI should be considered alongside other risk factors including waist circumference, blood pressure, and cholesterol levels. For men of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends slightly lower thresholds, as these groups face higher health risks at lower BMI levels. Use our free BMI calculator above to check your personal BMI instantly and see which category you fall into.
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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.
NHS Weight Management Support and When to Seek Help
If your BMI falls outside the healthy range, the NHS offers support through its weight management pathway. Your GP can assess your health and discuss lifestyle changes, including diet and physical activity. If weight-related health issues develop — such as type 2 diabetes, high blood pressure, or sleep apnoea — your GP may refer you to specialist tier 3 weight management services. These services provide structured support including dietary advice, behaviour change programmes, and in some cases, prescription weight management medication. The NHS emphasises that sustainable weight loss of around 0.5–1 kg per week, achieved through reduced-calorie eating and increased physical activity, is most effective long-term. Early intervention is important: even a modest 5–10% reduction in body weight can significantly improve health outcomes and reduce disease risk.
- 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 BMI accurate for men with lots of muscle?
No — BMI has significant limitations for muscular individuals. It cannot distinguish between muscle and fat, so athletes and people with high muscle mass may have a high BMI despite low body fat. Your GP can assess your overall health using additional measures like waist circumference and fitness level, which provide a more complete picture than BMI alone.
What's the difference between overweight and obese according to NHS?
The NHS defines overweight as BMI 25.0–29.9 and obese as BMI 30.0 or above. Obese is further divided into three classes based on severity. The distinction matters because obesity carries significantly higher risks for type 2 diabetes, cardiovascular disease, and other health conditions. Your GP can help you understand what your BMI means for your personal health.
Can I use BMI to check my ideal weight for my height?
Yes — the healthy BMI range helps determine a healthy weight for your height. For your height, multiply your height in metres by itself, then multiply by 18.5 and 24.9 to find your healthy weight range in kilograms. Alternatively, use our free BMI calculator above, which instantly calculates your healthy weight range based on your height.
Does ethnicity affect what's a good BMI?
Yes — the NHS recognises that people of South Asian, Chinese, Black African, and Black Caribbean heritage have higher health risks at lower BMI levels. For these groups, a healthy BMI range may start at 18.5–22.9 rather than 18.5–24.9. If you belong to one of these groups, discuss your personal BMI target with your GP to ensure it's appropriate for your ethnicity and health profile.
What should I do if my BMI is in the overweight or obese range?
Contact your GP for a health assessment. They can evaluate your overall health, check for weight-related conditions like high blood pressure or type 2 diabetes, and discuss lifestyle changes such as diet and exercise. If needed, your GP can refer you to NHS weight management services or specialist support. The NHS supports gradual, sustainable weight loss of around 0.5–1 kg per week for best long-term results.
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.