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 Using NHS Guidelines
Calculating your BMI (body mass index) is a simple way to check whether your weight is in a healthy range according to NHS standards. For men, the BMI formula divides your weight in kilograms by your height in metres squared. Our free BMI calculator above does this instantly, but understanding how it works and what your result means — especially within NHS guidance — helps you make informed health decisions. This guide explains the BMI formula, NHS categories, and when you should speak to your GP about your weight.
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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.
NHS BMI Categories and What They Mean for Men
The NHS BMI formula is straightforward: weight (kg) ÷ height (m)². The resulting number places you into one of five categories that guide health recommendations:
- Below 18.5: Underweight — your GP may recommend monitoring your nutrition
- 18.5–24.9: Healthy weight — this is the target healthy BMI range according to NHS guidance
- 25.0–29.9: Overweight — increased health risks begin to emerge
- 30.0–34.9: Obese (Class I) — NHS recommends speaking to your GP about weight management
- 35.0–39.9: Obese (Class II) — medical support recommended
- 40.0+: Severely obese (Class III) — urgent GP discussion recommended
For adult men, a healthy BMI sits between 18.5 and 24.9. However, BMI has limitations — it does not distinguish between muscle and fat, so athletes may have a higher BMI despite low body fat. Your GP considers other factors including waist circumference and overall health.
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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 Pathway and When to Seek Help
If your BMI falls outside the healthy range, the NHS offers a structured weight management pathway. Start with tier 1 self-help resources and your GP for initial advice. If needed, your GP can refer you to tier 3 specialist weight management services, where you may be offered structured programmes, behaviour change support, or prescription weight loss medications like GLP-1 injections. The NHS recommends losing weight gradually — around 0.5 to 1 kg per week — alongside a reduced-calorie diet and increased physical activity. Use our free BMI calculator above to check your current BMI, and discuss your individual health goals and options with your GP, who can provide personalised guidance based on your complete health picture.
- 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 BMI formula for men?
The BMI formula is weight (kg) ÷ height (m)². For example, a man weighing 85 kg who is 1.80 m tall would have a BMI of 85 ÷ (1.80)² = 26.2. Use our BMI calculator above for gradual improvement — it handles the maths automatically.
What is a healthy BMI range for men according to NHS guidance?
The NHS defines a healthy BMI for all adults, including men, as 18.5 to 24.9. A BMI above 25 is considered overweight, and above 30 is considered obese. Your GP can discuss what a healthy weight means for your individual circumstances.
When should I speak to my GP about my BMI?
If your BMI is 25 or above, or if you have health concerns related to your weight (such as high blood pressure or type 2 diabetes risk), contact your GP. They can assess your individual health and discuss weight management options tailored to you.
Does BMI work for muscular men?
BMI has limitations for very muscular men — muscle weighs more than fat, so athletes may have a higher BMI despite low body fat. Your GP can assess body composition alongside BMI to get a fuller health picture.
What does the NHS recommend if my BMI is in the obese range?
The NHS recommends speaking to your GP, who may suggest tier 3 specialist weight management services. These offer behaviour change programmes, lifestyle support, and in some cases, prescription weight loss medications. Weight loss of 5–10% can significantly improve health outcomes.
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.