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 Healthy Weight?
A healthy weight is different for everyone and depends on your height, age, sex, and body composition. According to NHS guidelines, a healthy weight range is defined by a BMI (body mass index) of 18.5 to 24.9. However, what counts as a healthy weight for you personally depends on your individual circumstances. Your GP can help you determine what a healthy weight means for your health. Use our free BMI calculator above to find your personal healthy weight range and see where you currently stand.
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.
Healthy Weight Range by Height
The NHS defines a healthy weight using BMI, which is calculated from your height and weight together. To find your healthy weight range for your height, multiply your height in metres by itself, then multiply by 18.5 and 24.9. For example, if you're 1.73m tall (5ft 8in), a healthy weight range is approximately 55kg to 74kg (8st 10lbs to 11st 8lbs). If you're of South Asian, Chinese, Black African, or Black Caribbean descent, the NHS recommends a slightly lower healthy weight range — a BMI of 18.5 to 22.9 — because these groups face higher health risks at lower BMI levels. You can also use our free weight converter to switch between kilograms, stone, and pounds to understand your healthy weight range in whichever units you prefer. The ideal body weight varies by individual, but staying within your BMI healthy range supports better long-term health outcomes.
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.
Using the BMI Framework for Personalised Guidance
The BMI healthy range is a useful starting point, but it's important to understand that BMI has limitations — it doesn't account for muscle mass, bone density, or where fat is stored on your body. Two people at the same weight and height can have very different body compositions. Your waist circumference is also important: the NHS recommends men keep their waist below 94cm (37in) and women below 80cm (31.5in) for reduced health risk. A healthy weight calculator like our free BMI tool takes your personal measurements into account and gives you a clearer picture. For a truly personalised assessment of what a healthy weight means for you, speak with your GP, who can consider your medical history, family genetics, and individual health goals. Your GP may also refer you to a dietitian or weight management specialist for tailored advice.
- 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 difference between healthy weight and ideal weight?
Healthy weight refers to a weight range associated with good health outcomes, typically defined by BMI 18.5–24.9. Ideal weight is a more personal concept based on your individual body composition, fitness level, and health goals. The two concepts overlap but aren't identical — you can be at a healthy weight by BMI standards and still have different personal fitness or body composition goals.
How do I know if I'm at a healthy weight for my height?
Calculate your BMI using your height and weight. According to NHS guidelines, a BMI between 18.5 and 24.9 is considered healthy. You can use our free BMI calculator on this page, which instantly shows your BMI category and healthy weight range for your specific height. If you're of South Asian or Black African heritage, lower thresholds (18.5–22.9) may apply.
What is the average UK weight, and how does it compare to healthy weight?
The average UK adult man weighs approximately 85.7kg (13st 7lbs) and the average woman weighs approximately 71.6kg (11st 3lbs). However, average weight is not the same as healthy weight — the NHS healthy weight range depends on individual height and BMI. Many UK adults are overweight by BMI standards, so average does not equal healthy.
Is BMI the only way to measure if I have a healthy weight?
BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat, so athletes may have a high BMI despite low body fat. Other measures like waist circumference, waist-to-height ratio, and body composition are also important. Your GP can assess your overall health using multiple measures, not just BMI.
What should I do if my weight isn't in the healthy range?
If your BMI falls outside the healthy range, speak with your GP. They can assess your individual health, discuss sustainable lifestyle changes, and refer you to support such as dietitians or weight management services if appropriate. Even small weight changes of 5–10% can improve health outcomes. Use our free progress tracker to monitor changes over time.
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.