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
Body Fat Level Chart — Understanding Your Results
Body fat percentage is a measure of the proportion of fat in your body compared to muscle, bone, and other tissues. Unlike BMI, which doesn't distinguish between muscle and fat, a body fat level chart gives you a clearer picture of your actual body composition. Whether you're tracking fitness progress or understanding your health risk, knowing where your body fat sits on a healthy range is valuable. This guide explains the standard reference ranges used in the UK and how to interpret your personal results.
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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 Interpret Your Body Fat Calculator Results
Body fat percentage is measured as a portion of your total body weight. The healthy ranges vary significantly by gender and age, reflecting natural differences in body composition between men and women.
- 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%+)
Most adults fall into the "Acceptable" range, which represents a healthy level for general health and wellbeing. If your body fat percentage falls outside these ranges, your GP can offer personalised guidance. Use our free BMI calculator on this page alongside a body fat assessment for a fuller picture of your body composition and health risk.
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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.
UK Guidance and Next Steps
Body composition matters because two people at the same weight can have vastly different body fat levels depending on muscle mass. This is why body fat vs BMI tells different stories. An athlete might have a BMI in the "overweight" range yet have very low body fat percentage because muscle is denser than fat. Our weight converter helps you track changes in total weight, while body fat measurement reveals what that weight is actually made of—essential for understanding whether weight changes reflect muscle gain or fat loss.
- 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 body fat percentage and BMI?
BMI measures weight relative to height but doesn't distinguish between muscle and fat. Body fat percentage directly measures the proportion of fat in your body. Two people with the same BMI can have very different body fat levels—an athlete might have high BMI but low body fat, while someone sedentary might have normal BMI but high body fat. Both metrics are useful: BMI is a screening tool, body fat is more specific.
Is visceral fat different from the body fat percentage shown on a chart?
Yes. Body fat percentage measures total body fat (subcutaneous and visceral). Visceral fat is the dangerous fat stored around internal organs. Unfortunately, standard body fat charts don't tell you specifically how much visceral fat you have—that requires imaging. However, waist circumference is a practical proxy: men over 102cm (40in) and women over 88cm (34.5in) typically have elevated visceral fat risk.
Can I use a body fat chart if I'm very muscular or an athlete?
Charts are less accurate for athletes because they were developed using average populations. A very muscular person might exceed the "acceptable" range but be perfectly healthy. Your GP can assess your individual circumstances. Body fat percentage is most useful when tracked over time to see whether your composition is improving—alongside overall fitness and health markers.
How often should I check my body fat percentage?
Monthly checks are reasonable if you're actively trying to change your body composition. More frequent measurements (weekly) can be discouraging because natural water retention and daily fluctuations affect results. Track trends over 8–12 weeks rather than obsessing over single measurements. Use our free progress tracker to log changes and identify real patterns.
Is there an ideal body fat percentage for health?
The "Acceptable" range (women 25–31%, men 18–24%) represents healthy levels for most people. Within this range, health outcomes are good. "Athletic" and "Fitness" ranges indicate excellent body composition, but are not required for good health. Focus on staying within or moving toward the healthy range rather than chasing elite athlete levels unless that's your specific goal.
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.