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's a Healthy BMI Range for Men?
A healthy body mass index range for adult men in the UK is between 18.5 and 24.9, according to NHS guidelines. This range indicates that your weight is proportionate to your height and associated with lower health risks. However, BMI is just one measure of health — your body composition, including lean body mass and body fat percentage, also matters. Use our free BMI calculator above to find your personal BMI instantly and see where you fall on the healthy weight scale.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 Interpret Your BMI Calculator Results
When you use the BMI calculator on this page, your result will fall into one of six categories according to NHS guidelines:
- Below 18.5: Underweight — may indicate you need to gain weight for optimal health
- 18.5–24.9: Healthy weight — associated with lower risk of weight-related health conditions
- 25.0–29.9: Overweight — increased risk of type 2 diabetes, high blood pressure, and heart disease
- 30.0–34.9: Obese (Class I) — significantly increased health risks
- 35.0–39.9: Obese (Class II) — higher risk of serious health complications
- 40.0+: Severely obese (Class III) — very high risk requiring medical attention
If you are of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply — your healthy weight range may start at a BMI of 18.5–22.9 instead. Your GP can discuss your individual risk factors and what your BMI means for your personal 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.
BMI vs Body Fat Percentage — Which Matters More?
BMI and body fat percentage measure different aspects of body composition. BMI is a simple calculation based on height and weight alone — it does not distinguish between muscle mass and fat. Two men with identical BMI can have very different body compositions. Body fat percentage is more precise but requires specialist measurement. A healthy body fat range for men is typically 10–20%, though this varies with age and fitness level. For most people, BMI remains a useful screening tool, but it works best alongside waist circumference measurements and professional health assessment. If you are concerned about your body composition, ask your GP about options including DEXA scanning or bioelectrical impedance analysis.
- 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 range is considered healthy for adult men in the UK?
The NHS defines a healthy BMI range for adult men as 18.5 to 24.9. This range is associated with lower risk of weight-related health conditions. However, BMI is just one health metric — body fat percentage, waist circumference, and overall fitness also matter. Use our free BMI calculator to find your personal result.
Does BMI work the same way for men and women?
Yes, the BMI formula and healthy ranges are identical for men and women. However, body fat percentage ranges differ by gender — healthy body fat for men is typically lower than for women. Men should aim for 10–20% body fat, while women's healthy range is usually 18–25%. Your body composition matters as much as your BMI.
I have a BMI of 27 — should I be concerned?
A BMI of 27 falls in the overweight category (25.0–29.9). This indicates increased risk of type 2 diabetes and cardiovascular disease, but it is not necessarily urgent. Your GP can assess your individual risk based on your health history, family background, waist circumference, and fitness level. Even a 5–clinically studied weight loss can improve your health.
Why do different ethnicities have different BMI thresholds?
Research shows that people of South Asian, Chinese, Black African, and Black Caribbean heritage have higher health risks at lower BMI levels compared to European populations. This is due to genetic factors and differences in how fat is distributed. If you are from one of these backgrounds, the NHS recommends using a healthy BMI range of 18.5–22.9 rather than 18.5–24.9.
Can I have a healthy BMI but high body fat percentage?
Yes — this is called "normal weight obesity." Someone can fall within a healthy BMI range but have high body fat and low lean body mass, especially if they are sedentary. Conversely, very muscular individuals may have high BMI but low body fat. This is why body composition assessment, including body fat percentage and fitness level, is important alongside BMI.
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.