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
Men's Body Mass Index — What You Need to Know
Body Mass Index (BMI) is a measurement of body weight relative to height, used by the NHS to assess whether men fall into a healthy weight range. For men in the UK, BMI is calculated by dividing weight in kilograms by height in metres squared. A healthy BMI is between 18.5 and 24.9, though men of South Asian, Chinese, Black African, or Black Caribbean heritage may have different risk thresholds. Understanding your BMI is a useful starting point for assessing your overall health, though it's important to remember that BMI has limitations and doesn't account for muscle mass or body composition. Use our free BMI calculator above to find your personal BMI instantly.
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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.
BMI Categories for Men and Healthy Weight Ranges
According to NHS guidelines, men's BMI falls into the following categories:
- Underweight: BMI below 18.5 — may indicate insufficient body weight
- Healthy weight: BMI 18.5 to 24.9 — associated with lower health risks
- Overweight: BMI 25.0 to 29.9 — increased risk of weight-related health conditions
- Obese (Class I): BMI 30.0 to 34.9 — significantly elevated health risks
- Obese (Class II): BMI 35.0 to 39.9 — high health risks
- Severely obese (Class III): BMI 40.0 and above — very high health risks
For men of South Asian, Chinese, Black African, or Black Caribbean backgrounds, the NHS recommends lower thresholds due to higher cardiovascular and diabetes risk at equivalent BMI levels. Your GP can discuss whether these adjusted thresholds apply to you. To calculate your healthy weight range for your height, multiply your height in metres squared by 18.5 (lower bound) and 24.9 (upper bound). For example, a man who is 1.75m tall should aim for a weight between 56.6 kg and 76.1 kg (approximately 8st 13lbs to 11st 13lbs).
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — 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 — 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 the Importance of Body Composition
While BMI is a useful screening tool, it has important limitations that men should understand. BMI does not distinguish between muscle and fat — muscular men, athletes, or those who exercise regularly may have a high BMI but low body fat percentage, meaning they are not at elevated health risk. Body composition (the ratio of fat to lean body mass) is often more accurate than BMI alone for assessing health. Additionally, BMI doesn't account for where fat is stored; visceral fat (around internal organs) carries greater health risks than subcutaneous fat (under the skin). The NHS recommends also measuring waist circumference: for men, a waist over 94cm (37 inches) indicates increased health risk, and over 102cm (40 inches) indicates high risk. Consider using our free weight converter and BMI calculator together to get a complete picture of your health status.
- 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.
How do I calculate my BMI as a man?
Divide your weight in kilograms by your height in metres squared. For example, if you weigh 85kg and are 1.80m tall: 85 ÷ (1.80 × 1.80) = 26.2. Use our free BMI calculator above for gradual improvement.
What is a healthy BMI for men in the UK?
According to NHS guidelines, a healthy BMI for men is between 18.5 and 24.9. If you are of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a healthy range of 18.5 to 22.9. Your GP can advise what's appropriate for you.
Why does BMI not account for muscle?
BMI only measures weight relative to height — it cannot distinguish between muscle and fat. Muscular men may have a high BMI despite low body fat percentage. For a more complete picture, consider measuring body fat percentage or waist circumference alongside BMI.
What health risks are associated with a high BMI for men?
A BMI above 25 increases risk of type 2 diabetes, heart disease, high blood pressure, certain cancers, and sleep apnoea. Even a modest weight loss of 5–10% of body weight can significantly reduce these risks.
Should men use different BMI thresholds based on ethnicity?
Yes. The NHS recommends lower BMI thresholds for men of South Asian, Chinese, Black African, and Black Caribbean heritage due to higher cardiovascular and metabolic risk at lower BMI levels. Discuss your personal thresholds with your GP.
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.