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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Body Fat Chart — Understanding Healthy Body Composition
A body fat chart shows the percentage of your body weight that is fat tissue, helping you understand your body composition beyond just BMI. In the UK, body fat percentage is increasingly recognised as an important health metric alongside weight and BMI. While BMI tells you whether your weight falls within a healthy range for your height, body fat percentage reveals whether that weight includes healthy muscle mass or excess fat. Understanding where your body fat sits on a health chart can help guide conversations with your GP about weight management and overall fitness.
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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.
UK Body Fat Percentage Ranges and Health Guidelines
The NHS and UK health professionals recognise body fat percentage as a valuable measure of body composition. Unlike BMI, which cannot distinguish between muscle and fat, body fat percentage gives a more detailed picture of your health.
- Women: Essential fat (10–13%), Athletic (14–20%), Fitness (21–24%), Acceptable (25–31%), Obese (32%+)
- Men: Essential fat (2–5%), Athletic (6–13%), Fitness (14–17%), Acceptable (18–24%), Obese (25%+)
These ranges are based on clinical evidence and used by UK fitness professionals and healthcare providers. A healthy body fat percentage depends on age, sex, and individual health goals. Your GP can advise on what range is appropriate for you. Remember that body fat percentage alone doesn't tell the whole story — factors like cardiovascular fitness, strength, and overall health matter equally. Use our free BMI calculator above alongside body fat assessment for a complete picture of your 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.
How to Use a Body Fat Chart for Your Health Journey
Body fat charts are most useful when tracked over time rather than relying on a single measurement. This allows you to see whether your weight management efforts are building muscle or reducing fat, which is especially important if you're following an exercise programme alongside dietary changes.
Methods to estimate body fat include skinfold measurements (used by GPs and fitness professionals), bioelectrical impedance scales (home scales), and DEXA scans (gold standard, available through private providers or some NHS services). Each has different accuracy levels — your GP can advise on the most appropriate method for your situation. Track your progress using our free progress tracker to monitor changes in weight and fitness over time, giving you a complete overview of your health journey.
- 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's the difference between BMI and body fat percentage?
BMI measures weight relative to height and cannot distinguish between muscle and fat. Body fat percentage directly measures the proportion of fat tissue in your body. A person with high muscle mass may have a high BMI but healthy body fat percentage. Both measurements together give a fuller picture of health than either alone.
Can I measure my body fat percentage at home?
Yes, using bioelectrical impedance scales, but accuracy varies. The most accurate methods are skinfold measurements by a trained professional or DEXA scans. Many UK gyms offer body composition analysis, and some NHS services provide this assessment. Your GP can advise on the most reliable method for your health needs.
Is a lower body fat percentage always better?
No. Essential fat (the minimum needed for survival and health) is 10–13% for women and 2–5% for men. Going below essential fat levels is unhealthy. A healthy body fat percentage depends on your age, sex, fitness level, and individual circumstances — discuss your personal target with your GP.
How does body fat percentage relate to weight loss injections?
Medications like Mounjaro and Wegovy help reduce weight, but they affect both fat and muscle. Tracking body fat percentage alongside weight loss shows whether you're preserving muscle mass. This is why combining medication with strength training and adequate protein is important for healthy body composition.
Should I use this chart to diagnose a health problem?
No. Body fat charts are for general information only. If you're concerned about your body composition or health, consult your GP. They can assess your individual situation, explain what your body fat percentage means for your health, and recommend appropriate next steps, whether that's lifestyle changes, further testing, or specialist assessment.
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.