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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How to Calculate BMI for Men
Calculating your BMI (Body Mass Index) is straightforward using a simple formula, and it's an important first step in understanding your health. The NHS uses BMI as a screening tool to assess whether an adult's weight falls within a healthy range. For men, the calculation is the same regardless of age — it's based purely on your height and weight. Use our free BMI calculator above to get your result instantly, or read on to learn how the calculation works and what your BMI means for your health.
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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.
How to Calculate BMI: The Formula and UK Ranges
The BMI formula is: BMI = weight (kg) ÷ height (m)²
For example, a man weighing 85 kg and 1.78 metres tall would have a BMI of 85 ÷ (1.78 × 1.78) = 26.8. You can calculate this manually or use our free BMI calculator above for gradual improvement.
Once you have your BMI, the NHS BMI categories UK are:
- Below 18.5: Underweight
- 18.5–24.9: Healthy weight
- 25.0–29.9: Overweight
- 30.0–34.9: Obese (Class I)
- 35.0–39.9: Obese (Class II)
- 40.0+: Severely obese (Class III)
The healthy BMI range for most UK men is 18.5 to 24.9. If your BMI falls between 25 and 29.9, you're in the overweight category, and an overweight BMI threshold of 30 marks the start of obesity according to NHS guidelines.
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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
While BMI is a useful screening tool, it has important BMI limitations. BMI does not distinguish between muscle and fat — so a man with high muscle mass may have a higher BMI but lower body fat. BMI also doesn't account for where fat is stored. Your waist circumference is equally important: the NHS recommends men aim for a waist below 94 cm (37 inches) for reduced health risk, or below 102 cm (40 inches) as an absolute limit.
For the most complete picture of your health, consider using our free weight converter to track changes over time, and discuss your personal BMI with your GP — they can assess your overall health alongside age, family history, and any existing health conditions.
- 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 the healthy BMI range for men in the UK?
According to NHS guidelines, a healthy BMI for most men is between 18.5 and 24.9. A BMI of 25.0–29.9 is classified as overweight, and 30.0 or above is classified as obese. However, your GP can give you personalised advice based on your individual health profile.
Does muscle affect BMI calculations?
Yes — BMI cannot distinguish between muscle and fat. Men with high muscle mass may have a higher BMI but lower body fat. This is one reason why BMI alone is not a complete picture of health. Waist circumference and body composition are also important indicators.
Should I use a different BMI chart if I'm over 65?
No — the same BMI categories apply to men of all ages. However, as you age, muscle naturally decreases and other health factors become more important. Your GP can advise on what a healthy weight means for you specifically.
What's the difference between BMI and body fat percentage?
BMI is calculated from height and weight alone. Body fat percentage measures the actual proportion of fat in your body. A man can have the same BMI but very different body fat percentages depending on his muscle mass. Body fat percentage is more accurate for assessing fitness.
Can I use the same BMI calculator for men and women?
Yes — the BMI formula is identical for men and women. However, healthy body composition differs slightly by sex. Women typically have a naturally higher body fat percentage. Our free BMI calculator works for everyone, but your GP can discuss gender-specific health recommendations.
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.