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 a Good BMI Range in the UK?
A good BMI range for most UK adults is between 18.5 and 24.9, according to NHS guidelines. This is called the "healthy weight" category. However, if you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a lower healthy BMI range of 18.5 to 22.9, as these groups face higher health risks at higher BMI levels. Your individual "good" BMI depends on your age, muscle mass, and overall health — not just a number. Use our free BMI calculator above to check your personal BMI instantly and see where you fall within the healthy range.
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 Healthy Weight Thresholds
The NHS defines a good BMI range using five standard categories. A BMI below 18.5 is underweight, 18.5–24.9 is healthy weight, 25.0–29.9 is overweight, 30.0–34.9 is obese (Class I), and 35.0 and above is severely obese. The healthy BMI formula is weight in kilograms divided by height in metres squared. For example, at 5ft 8in (1.73m), a healthy weight falls between approximately 55kg and 74.5kg, or 8 stone 8 lbs to 11 stone 10 lbs. The NHS BMI categories are the same for all adults aged 18 and over, though ethnicity-adjusted thresholds apply to certain groups. Use our BMI calculator to find your personal healthy BMI range based on your height — it shows both metric and UK stone measurements 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.
Important BMI Limitations and What "Good" Really Means
BMI is a useful screening tool, but it has significant limitations. A "good" BMI range doesn't account for muscle mass, bone density, or where fat is stored on your body. Athletes and people with high muscle may have a high BMI but low body fat. Age, pregnancy, and other health factors also matter. The NHS recommends checking your waist circumference alongside BMI — a good waist measurement is under 94cm (37 inches) for men and 80cm (31.5 inches) for women. For personalised advice about what a good BMI range means for your individual health, speak to your GP, as they can consider your full health picture, medications, and family history.
- 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 BMI range is considered healthy in the UK?
According to NHS guidelines, a healthy BMI for most UK adults is 18.5 to 24.9. However, the NHS recommends lower thresholds (18.5–22.9) for South Asian, Chinese, Black African, and Black Caribbean adults, as these groups face higher cardiovascular and diabetes risk at higher BMI levels.
How do I calculate whether my BMI is in a good range?
Use the BMI formula: weight (kg) ÷ height (metres)². For example, if you weigh 70kg and are 1.75m tall, your BMI is 70 ÷ (1.75)² = 22.9, which falls in the healthy range. Our free BMI calculator on this page does this instantly — just enter your weight and height in UK measurements.
Is BMI the only measure of good health?
No. BMI is just one screening tool. Waist circumference, body composition, muscle mass, fitness level, and overall health are also important. A "good" BMI doesn't assures good health, and a high BMI doesn't always mean poor health — context matters.
What if my BMI is just outside the healthy range?
If your BMI is between 25.0–29.9 (overweight category), the NHS recommends lifestyle changes like increased physical activity and dietary adjustments. If it's 30 or above with weight-related health conditions, speak to your GP about weight management support options available in your area.
Does the BMI good range change with age?
No — the NHS BMI categories are the same for all adults aged 18 and over. However, BMI may be less accurate in elderly people due to natural muscle loss with age. Your GP can advise whether BMI is the best measure for your individual situation.
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.