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 the Average BMI in the UK?
The average BMI in the UK is approximately 27.6 for adults, according to recent health surveys — placing the average adult in the overweight category by NHS standards. However, average BMI doesn't reflect healthy BMI. According to NHS guidance, a healthy bmi range sits between 18.5 and 24.9 for most adults, with lower thresholds recommended for people of South Asian, Chinese, Black African, or Caribbean heritage. Understanding where you fall within the bmi formula helps you assess your personal health risk, rather than simply comparing yourself to the national average.
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 categories are the standard framework used across UK health services to assess weight status. A healthy bmi threshold starts at 18.5 and extends to 24.9 for most UK adults. Here's how the official bmi range uk breaks down:
- Underweight: BMI below 18.5
- Healthy weight: BMI 18.5–24.9
- Overweight: BMI 25.0–29.9
- Obese (Class I): BMI 30.0–34.9
- Obese (Class II): BMI 35.0–39.9
- Severely obese (Class III): BMI 40.0 and above
For adults of South Asian, Chinese, Black African, or Black Caribbean backgrounds, the overweight bmi threshold drops to 23.0, and obesity begins at 27.5, because these populations face higher cardiovascular and diabetes risk at lower BMI levels. Use our free BMI calculator above to check where you fall within these NHS categories instantly.
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 Pathway and Support
The NHS weight management pathway offers structured support across four tiers. Tier 1 includes self-help and community programmes available to all. Tier 2 involves GP-based behaviour change support. Tier 3 provides specialist multidisciplinary weight management services, where prescription medications like GLP-1 injections may be considered for eligible adults. Tier 4 covers bariatric surgery for severe obesity with significant health complications. Your GP can assess which tier is appropriate for you and refer you onward if needed. Many regions now offer access to weight loss medications through NHS specialist services, though availability and waiting times vary across ICBs.
- 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's the difference between average BMI and healthy BMI in the UK?
Average BMI reflects what most UK adults actually weigh (approximately 27.6), but healthy BMI is the NHS-recommended target of 18.5–24.9 for optimal health. The average being higher shows many UK adults are overweight; it doesn't define what's healthy. Your personal healthy weight depends on your height, age, and health conditions.
Do BMI limitations matter when comparing to the UK average?
Yes. BMI doesn't distinguish muscle from fat, so athletes or very muscular individuals may have a high BMI despite low body fat. BMI also doesn't account for where fat is stored — waist circumference matters for health risk. Use our free weight converter and BMI calculator together to get a fuller picture beyond the number alone.
Why are NHS BMI thresholds lower for some ethnic groups?
People of South Asian, Chinese, Black African, and Caribbean heritage have higher risk of type 2 diabetes and heart disease at lower BMI levels due to genetic and metabolic factors. NHS guidance recommends lower thresholds (overweight from 23, obesity from 27.5) to catch health risks earlier in these populations.
How can I check if my BMI is in the healthy range?
Calculate your BMI using the free BMI calculator on this page by entering your height and weight. The calculator shows you where you fall within NHS categories instantly. If you're concerned about your weight or health, your GP can provide personalised guidance specific to your circumstances.
What should I do if my BMI is above the NHS healthy range?
Start by speaking with your GP, who can assess your overall health, discuss any weight-related health conditions, and recommend support options. These may include lifestyle changes, referral to a tier 2 or 3 weight management service, or in some cases, prescription weight management medications like GLP-1 injections.
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.