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
What Is an NHS Weight Chart?
An NHS weight chart is a clinical tool used across UK health services to classify body weight and assess health risk. Unlike simple height-weight tables, NHS weight charts use BMI (body mass index) categories aligned with UK health guidance, helping GPs and patients understand whether a weight falls within a healthy range. This guide explains how NHS weight charts work, what the categories mean, and how to use them for your own health management.
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 NHS Weight Classifications
The NHS uses five main weight categories based on BMI (body mass index), which is calculated from your height and weight. These categories are:
- Underweight: BMI below 18.5 — may indicate nutritional concerns
- Healthy weight: BMI 18.5–24.9 — associated with lowest health risk
- Overweight: BMI 25.0–29.9 — increased risk of weight-related health conditions
- Obese (Class I): BMI 30.0–34.9 — higher health risk
- Obese (Class II): BMI 35.0–39.9 — significantly elevated health risk
- Severely obese (Class III): BMI 40.0+ — very high health risk
Your GP may refer to these categories to discuss weight management options. Use our free BMI calculator above to check where you fall and get personalised context for your height.
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.
Ethnicity-Adjusted NHS Guidance
Importantly, the NHS recognises that weight-related health risks vary by ethnicity. Adults of South Asian, Chinese, Black African, and Black Caribbean backgrounds have a higher risk of type 2 diabetes and cardiovascular disease at lower BMI levels. The NHS recommends lower thresholds for these groups: healthy weight BMI 18.5–22.9, overweight 23.0–27.4, and obese 27.5+. This means a BMI that might be classified as "overweight" for a white European adult could represent increased risk for someone of South Asian heritage. Your GP can discuss whether adjusted thresholds apply to you and what this means for your health management and weight guidance.
- 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.
How do I find my weight on an NHS weight chart?
First, find your height on the chart's vertical axis and your weight on the horizontal axis. Where they meet shows your BMI category. Alternatively, use our free BMI calculator on this page — enter your height and weight in kg, stone, or pounds, and it instantly shows your NHS category and healthy weight range for your height.
What does "healthy weight" mean on an NHS chart?
A healthy weight is one where your BMI falls between 18.5 and 24.9. This range is associated with the lowest risk of weight-related health conditions like type 2 diabetes, high blood pressure, and heart disease. However, NHS guidance notes that healthy weight alone doesn't assures health — waist circumference and overall fitness also matter.
Are NHS weight charts accurate for everyone?
NHS weight charts are useful screening tools but have limitations. They don't distinguish between muscle and fat (so athletes may have high BMI but low health risk), don't account for where fat is stored (belly fat is riskier), and may not be accurate for elderly people or during pregnancy. Your GP can discuss whether your personal circumstances affect how the chart applies to you.
Can I use an NHS weight chart if I'm pregnant?
Standard NHS weight charts don't apply during pregnancy, as weight gain is expected and necessary. The NHS provides separate pregnancy-specific weight guidance. Discuss weight management during pregnancy with your midwife or GP rather than using standard BMI charts.
What should I do if my weight falls in the "overweight" or "obese" category?
If your weight places you in a higher BMI category, it's worth discussing with your GP. They can assess your individual health, check for weight-related conditions, and discuss options including lifestyle changes, NHS weight management services, or in some cases, prescription weight loss treatment. Even a 5–10% weight reduction can bring meaningful health benefits.
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.