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
BMI Height and Weight Chart — NHS Guidelines
A BMI height and weight chart helps you understand whether your weight falls within a healthy range for your height according to NHS standards. Using the BMI formula and NHS categories, you can quickly see where you stand and whether your weight poses any health risks. This guide explains the official NHS BMI ranges, how to interpret them, and what to do next if you're concerned about your weight.
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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 BMI Categories and What They Mean
The NHS uses five BMI categories to classify adult weight status. These are based on BMI calculated from your height and weight using the standard BMI formula: weight (kg) divided by height (m) squared.
- Underweight: BMI below 18.5 — may indicate nutritional concerns
- Healthy weight: BMI 18.5 to 24.9 — associated with lowest health risks
- Overweight: BMI 25.0 to 29.9 — increased risk of weight-related conditions
- Obese (Class I): BMI 30.0 to 34.9 — significant health risk
- Obese (Class II): BMI 35.0 to 39.9 — high health risk
- Severely obese (Class III): BMI 40.0 and above — very high health risk
For adults of South Asian, Chinese, Black African, or Black Caribbean backgrounds, the NHS recommends lower thresholds because these groups face higher disease risk at the same BMI. For these populations, a healthy BMI range is 18.5 to 22.9, and overweight begins at 23.0.
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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.
NHS Weight Management Pathway and Next Steps
If your BMI falls outside the healthy range, the NHS offers a structured pathway to support. Tier 1 services include self-help tools, digital programmes, and community weight management. If you need more help, your GP can refer you to Tier 2 or Tier 3 specialist services, where you may receive structured behaviour change support or prescription weight loss treatment. Use our free BMI calculator above to check your personal BMI, then discuss results with your GP if you have concerns. Remember that BMI has limitations — it doesn't distinguish between muscle and fat, so your GP will also consider your waist circumference and overall health picture.
- 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 a healthy BMI according to the NHS?
According to NHS guidance, a healthy BMI for most UK adults is between 18.5 and 24.9. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a healthy range of 18.5 to 22.9 due to higher health risks at higher BMI levels in these populations.
How is BMI calculated?
BMI is calculated using the formula: weight in kilograms divided by height in metres squared (kg/m²). For example, a person weighing 70kg and 1.73m tall would have a BMI of 70 ÷ (1.73)² = 23.4. Our BMI calculator on this page calculates this instantly for you.
What are the limitations of using a BMI chart?
BMI limitations include that it cannot distinguish between muscle and fat — athletes may have a high BMI but low body fat. BMI also doesn't account for where fat is stored (waist circumference matters) and may be less accurate for elderly adults or during pregnancy. Your GP considers BMI alongside other health measures.
When should I see my GP about my BMI?
If your BMI is below 18.5 or above 25, it's worth discussing with your GP, especially if you have weight-related health conditions like high blood pressure, type 2 diabetes, or sleep apnoea. Your GP can assess your individual health and discuss whether support or treatment may help.
What does the NHS offer for weight management?
The NHS offers a tiered pathway starting with self-help tools and community programmes (Tier 1), progressing to GP-led behaviour change support (Tier 2), specialist multidisciplinary services including possible prescription medication (Tier 3), and bariatric surgery for severe obesity (Tier 4). Access varies by region and availability.
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.