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
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What's a Healthy Weight According to Your Height?
Your healthy weight depends on your height, age, and body composition — there's no single target number that applies to everyone. The NHS uses BMI (Body Mass Index) as the main screening tool to determine if a weight falls within a healthy range for a given height. A healthy BMI is between 18.5 and 24.9 for most UK adults, though ethnicity-adjusted thresholds apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage. This guide explains how to calculate your personal healthy weight range and what the numbers mean for your health.
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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.
How to Calculate Your Healthy Weight Range
To find your healthy weight range, you need your height and can then use the BMI formula to work backwards. The healthy BMI range is 18.5 to 24.9 for most adults. Here's how:
- Lower healthy weight: 18.5 × height(m)² = minimum healthy weight in kg
- Upper healthy weight: 24.9 × height(m)² = maximum healthy weight in kg
For example, an adult who is 5ft 8in (1.73m) tall would have a healthy weight range of approximately 55.4 kg to 74.5 kg (8st 10lbs to 11st 10lbs). Use our free BMI calculator above to find your personal range instantly, or use the weight converter to switch between kg, stone, and pounds. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the healthy range is slightly lower: 18.5 to 22.9 BMI, because these groups face higher health risks at the same weight. Your GP can advise you on what's healthy for your individual circumstances.
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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.
Why Height Matters More Than You Might Think
Height is crucial because body weight distributes across your frame — the same weight looks very different on someone 5ft tall versus someone 6ft tall. A 13-stone person who is 5ft 2in is likely to be overweight, but a 13-stone person who is 6ft 2in may be within a healthy range. This is why BMI uses both weight and height in its calculation. However, BMI has limitations: it doesn't distinguish between muscle and fat, so very muscular people may have a high BMI despite low body fat. It also doesn't account for where fat is stored — waist circumference matters too. The NHS recommends men keep their waist below 94cm (37in) and women below 80cm (31.5in) for health. Use our weight management calculator to explore how your weight relates to your height, and discuss your personal healthy weight with your GP.
- 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.
How do I convert my height to metres for the BMI calculation?
Divide centimetres by 100, or use this quick conversion: 5ft = 1.52m, 5ft 6in = 1.68m, 6ft = 1.83m. Our height converter tool makes this instant.
Is the healthy weight range the same for men and women?
The BMI categories (18.5–24.9 for healthy weight) are the same for all adults. However, women typically have higher natural body fat percentages than men, so some health professionals use slightly different body fat percentage targets — but BMI thresholds remain identical.
What if I'm taller or shorter than average — does my healthy weight change more?
Yes, significantly. Because BMI squares your height in the formula, small differences in height create larger differences in healthy weight ranges. A 1-inch height difference can change your healthy range by several kilograms. Use the BMI calculator to see your exact range.
Should I aim for the middle of the healthy weight range or can I be at either end?
Both ends of the healthy range (18.5–24.9 BMI) are medically healthy. Your ideal weight depends on genetics, muscle mass, and frame size. Some people naturally sit at 20 BMI, others at 24. Discuss with your GP what's realistic and sustainable for you personally.
My weight is within the healthy range but I'm still worried — what should I do?
BMI is a screening tool, not a complete health picture. If you have concerns about weight or health, book an appointment with your GP. They can assess your individual situation, check your waist circumference, and give personalised advice about weight management and health. ```
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.