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
Understanding Weight Charts and UK Health Guidelines
A weight chart helps you see where your current weight falls against NHS healthy weight ranges for your height. Whether you're checking your own weight or understanding healthy weight management in UK measurements, knowing the difference between underweight, healthy, overweight, and obese categories is important for your health. Our free BMI calculator above gives you personalised results instantly, and we've included practical context using stone, pounds, and kilograms so you can track your progress effectively.
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 UK Weight Charts Work
Weight charts are based on BMI (Body Mass Index), which divides your weight in kilograms by your height in metres squared. The NHS uses these standard categories for UK adults:
- Underweight: BMI below 18.5 — may need dietary review
- Healthy weight: BMI 18.5–24.9 — associated with lowest health risks
- Overweight: BMI 25.0–29.9 — increases risk of health conditions
- Obese (Class I): BMI 30.0–34.9 — significantly increases health risks
- Obese (Class II): BMI 35.0–39.9 — high health risk
- Severely obese (Class III): BMI 40.0+ — very high health risk
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds because these populations face higher risks of type 2 diabetes and cardiovascular disease at the same BMI levels. Your GP can discuss what healthy weight means for your individual circumstances.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Finding Your Healthy Weight Range
To find your healthy weight range, multiply your height in metres by itself, then multiply by 18.5 and 24.9. For example, if you're 1.70m tall: healthy range = 53.5–71.2 kg (8st 5lbs to 11st 2lbs). Use our free weight converter above to switch between kg, stone, and pounds easily. Even losing just 5–10% of your current weight can reduce blood pressure, improve blood sugar control, and lower cholesterol. If you're considering weight management options including medication, our GLP-1 weight loss calculator can help you understand potential outcomes alongside diet and exercise 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.
What is the healthy weight range for someone 5ft 8in (173cm) tall?
For 1.73m height, the healthy BMI range is approximately 55–74 kg (8st 8lbs to 11st 10lbs). Use our BMI calculator and weight converter above to find your exact range. Individual factors like muscle mass, frame size, and health conditions also matter — your GP can give personalised guidance.
Why do weight charts use different thresholds for different ethnic groups?
Research shows that people of South Asian, Chinese, Black African, and Black Caribbean heritage have higher risks of type 2 diabetes and heart disease at lower BMI levels. The NHS therefore recommends lower healthy weight thresholds for these populations. This reflects biology, not appearance — it's about individual health risk.
Is BMI the only measure I should use?
BMI is useful but has limitations. It doesn't distinguish between muscle and fat, so athletes may have high BMI but low body fat. Waist circumference is also important — men with waist over 102cm and women over 88cm face increased health risks regardless of BMI. Your GP can assess your overall health picture.
How much weight should I aim to lose per week?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week for sustainable results. This typically requires a calorie deficit of around 500 kcal daily, achieved through diet and increased physical activity combined. Very gradual weight management can lead to muscle loss and nutritional deficiencies.
Can weight loss medications like Wegovy help me reach my healthy weight?
Wegovy (semaglutide) is a prescription-only injection that may help weight management alongside diet and exercise changes. Clinical trials showed average weight loss of around 15% of body weight. Individual results vary significantly, and you'd need a clinical assessment to see if it's suitable for you — your GP or a licensed prescriber can discuss options.
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.