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
BMI Formula for Men — How to Calculate Your BMI
The BMI formula for men is straightforward: divide your weight in kilograms by your height in metres squared (kg ÷ m²). This simple calculation gives you a BMI number that the NHS uses to assess whether you're in a healthy weight range. Understanding your BMI and what it means for your health is an important first step in weight management. Use our free BMI calculator above to work this out instantly, or read on to learn how to calculate it manually and what your result means according to NHS guidance.
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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 Formula and Categories for Men
The BMI formula is the same for all adults, regardless of gender: BMI = weight (kg) ÷ height (m)². For example, a man weighing 85kg with a height of 1.80m would calculate: 85 ÷ (1.80 × 1.80) = 85 ÷ 3.24 = 26.2 BMI.
According to NHS BMI categories, this falls in the overweight range. The NHS uses these standard categories:
- 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)
For men of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds, with the healthy BMI range starting at 18.5–22.9. If you're unsure where you fit, our BMI calculator gives gradual improvement with NHS context.
Clinically BackedWeight Loss
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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 and When to Seek Help
The NHS recommends that men with a BMI range of 25–29.9 (overweight) or 30 or above (obese) consider lifestyle changes such as reduced-calorie diet and increased physical activity. If you have a BMI of 27 or above alongside weight-related health conditions—such as type 2 diabetes, high blood pressure, or heart disease—your GP may discuss prescription weight management options with you.
The NHS offers a structured weight management pathway through tier 3 specialist services in many areas, though access varies by region. Your GP can assess your individual situation and discuss whether medication, behaviour change support, or other interventions might help. Sustainable weight loss typically occurs at 0.5–1 kg per week alongside lifestyle changes.
The NHS recommends that men with a BMI range of 25–29.9 (overweight) or 30 or above (obese) consider lifestyle changes such as reduced-calorie diet and increased physical activity. If you have a BMI of 27 or above alongside weight-related health conditions—such as type 2 diabetes, high blood pressure, or heart disease—your GP may discuss prescription weight management options with you.
The NHS offers a structured weight management pathway through tier 3 specialist services in many areas, though access varies by region. Your GP can assess your individual situation and discuss whether medication, behaviour change support, or other interventions might help. Sustainable weight loss typically occurs at 0.5–1 kg per week alongside lifestyle changes.
- 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 (weight ÷ height²). For example: if you weigh 80kg and are 1.75m tall, your BMI is 80 ÷ (1.75 × 1.75) = 26.1. Our free BMI calculator above does this instantly for you.
What is a healthy BMI for men according to NHS guidance?
The NHS defines a healthy BMI as 18.5–24.9 for most men. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the healthy range is 18.5–22.9 due to higher health risks at lower BMI levels in these populations.
Does BMI work the same way for men and women?
Yes, the BMI formula is identical for all adults. However, body fat percentage distribution differs between sexes, so the same BMI may correspond to different body composition in men versus women. BMI is a screening tool, not a complete picture of health.
What are the limitations of BMI as a health measure?
BMI doesn't distinguish between muscle and fat, so athletes may have a high BMI despite low body fat. It also ignores where fat is stored. The NHS recommends checking waist circumference alongside BMI—for men, over 102cm indicates increased health risk.
When should I contact my GP about my BMI?
Contact your GP if your BMI is 30 or above, or 27–29.9 with weight-related health conditions. Your GP can assess your individual situation and discuss whether lifestyle support, behaviour change programmes, or prescription weight management might help you.
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.