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
Weight and Your Health — NHS UK Guidance
Weight management is one of the most important factors affecting long-term health in the UK. Whether you're concerned about your current weight, working towards a healthier weight, or simply want to understand how weight relates to your wellbeing, it's essential to have accurate information and access to practical tools. The NHS provides clear guidance on healthy weight ranges, and our free health calculator tools can help you assess your personal situation and track your progress. This guide explains what healthy weight means in the UK, how it's measured, and what support is available to you.
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.
Understanding Healthy Weight and NHS Guidance
Healthy weight is defined by the NHS using BMI (Body Mass Index), which takes your height and weight into account. For most UK adults, a healthy BMI falls between 18.5 and 24.9. However, thresholds differ for people of South Asian, Chinese, Black African, or Black Caribbean heritage — the NHS recommends lower starting points of 18.5 to 22.9 for these groups because they face higher health risks at lower BMI levels.
Your weight affects risk of serious health conditions including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers. Even modest weight loss of 5–10% of your body weight can deliver meaningful health improvements. The NHS recommends losing weight at a gradual, sustainable rate of 0.5 to 1 kg per week, alongside a reduced-calorie diet and increased physical activity.
- Use our free BMI calculator to check your personal BMI instantly
- NHS guidance applies across all four nations: England, Scotland, Wales, and Northern Ireland
- Weight management is available through NHS services at multiple tiers, from digital tools to specialist services
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.
Weight Converters and Practical Tools for UK Health
The UK uses a unique mix of measurements for weight — stone and pounds remain the preferred everyday units for most UK adults, whilst the NHS uses kilograms clinically. Our free weight converter helps you switch between kg, stone, and lbs instantly, making it easy to understand your weight in whichever units you prefer. This is especially helpful when using NHS health information or comparing your weight across different contexts.
To support your weight management journey, MyWeightCheck provides a free progress tracker where you can log your weight weekly and visualise your progress over time. Combined with our BMI calculator and weight converter, these tools give you everything needed to monitor your health effectively. If you're considering prescription weight loss support, our GLP-1 weight loss calculator can help you understand potential outcomes. Always discuss your weight management plans with your GP — they can provide personalised advice based on your individual health 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 is considered a healthy weight in the UK?
The NHS defines healthy weight using BMI. For most UK adults, a BMI between 18.5 and 24.9 is considered healthy. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a healthy BMI of 18.5 to 22.9. Your GP can advise what healthy weight means for you personally, considering your individual health factors.
How quickly should I aim to lose weight?
The NHS recommends losing weight at a rate of 0.5 to 1 kg (1 to 2 lbs) per week for sustainable results. This gradual approach is more likely to result in lasting weight loss and is safer than gradual weight management. Aim for a calorie deficit of approximately 500 kcal per day through diet and activity changes.
How can I check if my weight is healthy for my height?
Use our free BMI calculator on this page to check your BMI instantly — it accounts for your height and gives you your personal BMI score and healthy weight range. You can also use our weight converter to switch between kg, stone, and lbs. If you have concerns, your GP can provide personalised guidance.
What weight-related health conditions might affect my eligibility for weight loss support?
Conditions include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, and history of heart disease or stroke. If you have a BMI of 27–29.9 with any of these conditions, you may be eligible for prescription weight loss treatment. Your GP can assess your suitability.
Where can I find NHS weight management support?
The NHS offers weight management through multiple routes: digital tools and online programmes (Tier 1), primary care interventions (Tier 2), specialist multidisciplinary services (Tier 3), and bariatric surgery for severe obesity (Tier 4). Ask your GP for a referral to services in your area, or use the NHS weight loss plan online.
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.