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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Understanding Your Healthy Weight Range in the UK
Your healthy weight range is the span of weights that, for your height, puts you in the healthy BMI category according to NHS guidelines. Rather than aiming for one exact weight, NHS health advice encourages you to work towards any weight within your personal range, as this supports sustainable weight management and better long-term outcomes. Understanding your individual range helps you set realistic, health-focused goals without the pressure of hitting a single number.
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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 Calculate Your Healthy Weight Range
Your healthy weight range is calculated using the BMI formula, which divides your weight in kilograms by your height in metres squared. According to NHS guidance, a healthy BMI falls between 18.5 and 24.9 for most adults. To find your personal range, multiply your height squared by both 18.5 and 24.9 — this gives you the lower and upper bounds of your healthy weight.
For example, if you're 1.73 metres tall (5ft 8in), your healthy weight range is approximately 55.4 kg to 74.5 kg (or 8st 10lbs to 11st 10lbs). Important: For people of South Asian, Chinese, Black African, or Black Caribbean heritage, NHS guidance recommends lower thresholds — a healthy BMI range of 18.5 to 22.9 — because these groups face higher health risks at higher BMI levels.
Use our free BMI calculator above to find your exact personal healthy weight range instantly, rather than calculating manually.
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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.
Why Your Range Matters More Than One Target Weight
Setting a range rather than a single target weight takes pressure off and makes weight management more sustainable. Most people naturally fluctuate by 1–2 kg week-to-week due to water retention, hormones, and digestion — focusing on staying within your range rather than hitting one exact number reduces stress and helps you stick with healthy habits long-term.
The NHS also recognises that your ideal weight depends on muscle mass, bone density, and individual health factors — not just height and weight. Even reaching the lower end of your healthy range can bring significant health benefits including better blood pressure control, improved blood sugar levels, and reduced joint strain. Your GP can discuss what a realistic and healthy target within your range means for your individual circumstances.
- 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 a healthy weight and my personal healthy range?
Your healthy weight range is the full span of weights that gives you a healthy BMI (18.5–24.9) for your height. Any weight within that range is considered healthy for you. A single "ideal" weight is less realistic because factors like muscle, bone density, and individual health vary between people — your range gives you flexibility.
Does my healthy weight range change if I'm very muscular or athletic?
BMI doesn't distinguish between muscle and fat, so athletic individuals may have a higher BMI despite low body fat. If you're very muscular, discuss your healthy weight with your GP rather than relying solely on BMI. Your GP can assess body composition and give personalised guidance that accounts for your muscle mass.
Are healthy weight ranges different for women and men?
No — the BMI categories and healthy ranges are the same for men and women. However, men and women typically have different amounts of body fat at the same BMI, so two people with the same BMI may look different. Individual health goals should always be discussed with your GP.
How can I find my healthy weight range if I'm of South Asian or Black African heritage?
According to NHS guidance, adults of South Asian, Chinese, Black African, or Black Caribbean heritage should use lower BMI thresholds: 18.5 to 22.9 is healthy, 23 to 27.4 is overweight, and 27.5+ is obese. Use our BMI calculator above and select your ethnicity to see your personalised range and category.
Is losing weight within my healthy range assured to improve my health?
While reaching a healthy weight reduces health risks, other factors matter too — regular physical activity, sleep quality, stress management, and diet quality are equally important. Even modest weight loss of 5–10% of your current weight can improve blood pressure and blood sugar control. Always consult your GP for personalised health advice beyond weight.
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.