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 NHS Guidance for UK Adults
Understanding your weight and how it affects your health is an important part of staying well. The NHS provides clear guidance on healthy weight ranges for UK adults, along with practical support and resources to help you manage your weight effectively. Whether you're looking to understand what a healthy weight means for you, or you want to explore weight management options available through the NHS, this guide covers everything you need to know about weight and UK health guidance.
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.
NHS Weight Guidance and Healthy Weight Ranges
The NHS defines a healthy weight range using BMI (Body Mass Index), which is calculated from your height and weight. According to NHS guidance, a healthy BMI for most UK adults is between 18.5 and 24.9. You can calculate your personal BMI instantly using our free BMI calculator above to see where you fall on the NHS scale.
- Healthy weight (BMI 18.5–24.9): Associated with lower health risks
- Overweight (BMI 25.0–29.9): May increase risk of health conditions
- Obese (BMI 30.0–34.9): Higher risk of type 2 diabetes, heart disease, and other conditions
- Severely obese (BMI 40+): Significantly increased health risks
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds due to higher health risks at lower weights. Waist measurement is also important — the NHS advises monitoring your waist circumference alongside BMI as an indicator of health risk.
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.
NHS Weight Management Support and Resources
If you're concerned about your weight, the NHS offers a structured weight management pathway across four tiers of support. You can start with self-help resources and digital tools like the NHS Weight Loss Plan, progress to your GP for behaviour change support, or be referred to specialist weight management services. Our free weight converter helps you track your weight in kilograms, stone, or pounds — whichever you prefer — making it easier to monitor your progress over time. Many regions also offer community weight management programmes and specialist services where prescription weight loss medications may be considered for eligible adults.
- 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 does the NHS say is a healthy weight?
The NHS defines healthy weight using BMI categories. A healthy BMI is 18.5 to 24.9 for most UK adults. However, there's a range of healthy weights depending on your height. Use our BMI calculator above to find your healthy weight range based on your specific height. For people of South Asian or Black African heritage, lower thresholds apply (18.5 to 22.9).
How can I access weight management support through the NHS?
Start by speaking to your GP, who can assess your situation and discuss options. The NHS offers a four-tier pathway: tier 1 includes self-help and digital tools; tier 2 provides GP-led behaviour change support; tier 3 offers specialist multidisciplinary services; and tier 4 covers bariatric surgery for severe obesity. Availability varies by region and local integrated care board.
What is a healthy weight loss rate according to NHS guidance?
The NHS recommends losing weight at a rate of 0.5 to 1 kg (1 to 2 lbs) per week for sustainable, healthy weight loss. This typically requires a calorie deficit of around 500 kcal per day. Faster weight loss can result in muscle loss and isn't recommended without medical supervision.
Does the NHS prescribe weight loss medications?
Yes, the NHS can prescribe weight loss medications such as tirzepatide (Mounjaro) and semaglutide (Wegovy) through specialist tier 3 weight management services for eligible adults. Eligibility is based on BMI and health conditions. Access varies significantly by region, and waiting lists can be long in some areas.
What is the NHS health advice on waist measurement?
The NHS recommends monitoring waist circumference alongside BMI. For men, a waist over 94 cm (37 inches) indicates increased health risk; over 102 cm (40 inches) indicates high risk. For women, increased risk starts at 80 cm (31.5 inches) and high risk at 88 cm (34.5 inches).
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.