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 Weight Chart — What NHS Recommends
A BMI height weight chart shows whether your weight falls within a healthy range for your height according to NHS guidelines. Your BMI (body mass index) is calculated from your height and weight, and NHS thresholds help determine if you're at a healthy weight, overweight, or obese. This guide explains the NHS BMI formula, categories, and what the numbers mean for your health — plus when to seek support from your GP.
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 BMI Categories and What They Mean
The NHS BMI formula is simple: weight in kilograms divided by height in metres squared (kg/m²). Using our free BMI calculator above, you can instantly find your BMI by entering your height and weight. The NHS divides BMI into five clear categories:
- Underweight: BMI below 18.5 — may indicate insufficient nutrition or underlying health issues
- Healthy weight: BMI 18.5–24.9 — the target range for most UK adults
- Overweight: BMI 25.0–29.9 — increased risk of weight-related health conditions
- Obese (Class I): BMI 30.0–34.9 — significant health risks increase
- Obese (Class II): BMI 35.0–39.9 — higher health risks
- Severely obese (Class III): BMI 40.0+ — very high health risks
Important: For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds because these groups face higher cardiovascular and diabetes risk at lower BMI levels.
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 — When to Speak to Your GP
If your BMI falls outside the healthy range, your GP can offer personalised advice and support. The NHS follows a structured weight management pathway starting with self-help resources and lifestyle changes, progressing to specialist services if needed. Many people benefit from structured programmes combining diet, physical activity, and behavioural support. Use our free weight converter to track your weight in the units you prefer, and consider our BMI calculator to monitor changes over time. Your GP may refer you to a tier 3 specialist weight management service if additional support is needed — availability varies by region, so speak to your practice about local options.
- 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 BMI formula and how do I calculate it?
BMI = weight (kg) divided by height (metres) squared. For example, someone weighing 70kg and 1.75m tall would have a BMI of 70 ÷ (1.75 × 1.75) = 22.9, which is healthy. Our free BMI calculator does this instantly — just enter your height and weight.
Why does the NHS have different BMI thresholds for some ethnic groups?
Research shows that people of South Asian, Chinese, Black African, and Black Caribbean descent develop weight-related health conditions like type 2 diabetes at lower BMI levels than European populations. The NHS recommends lower thresholds (healthy: 18.5–22.9) for these groups to identify risk earlier.
What are the limitations of using BMI as a health measure?
BMI doesn't distinguish between muscle and fat — athletes may have high BMI but low body fat. It doesn't account for where fat is stored (waist circumference matters too) or individual variations in bone density. BMI is a screening tool, not a complete health assessment. Your GP can provide context specific to your health.
Is being in the overweight BMI range always unhealthy?
Not necessarily. While overweight BMI (25–29.9) is associated with increased health risks, some individuals with BMI in this range may be metabolically healthy. However, NHS guidance recommends aiming for the healthy weight range (BMI 18.5–24.9) for most people. Your GP can assess your individual risk factors.
How quickly should I aim to lose weight if my BMI is high?
The NHS recommends losing weight gradually — around 0.5 to 1 kg per week is considered safe and sustainable. Faster weight loss can cause muscle loss and nutritional deficiencies. Your GP or a specialist weight management service can create a personalised plan suited to your health and circumstances.
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.