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's the Appropriate Weight For Your Height?
Finding your appropriate weight for height depends on several factors including age, sex, muscle mass, and overall health. In the UK, the NHS uses BMI (body mass index) as the primary screening tool to determine if your weight falls within a healthy range for your height. However, weight alone doesn't tell the whole story — your individual health, fitness level, and medical history all matter. Our free BMI calculator and weight converter can help you check where you stand and understand what a healthy weight means for your specific measurements.
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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.
NHS Healthy Weight Ranges By Height
The NHS defines a healthy BMI as 18.5 to 24.9 for UK adults, which translates to different weight ranges depending on your height. For example, at 5ft 8in (173cm), the healthy weight range is approximately 8st 7lbs to 11st 7lbs (55–73kg). For someone 5ft 5in (165cm), the healthy range is roughly 7st 8lbs to 10st 3lbs (48–65kg).
It's important to note that ethnicity affects health risk at different BMI levels. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — a healthy BMI starts at 18.5 but extends only to 22.9 rather than 24.9. This is because these populations face higher risk of type 2 diabetes and heart disease at lower BMI levels.
Use our free weight converter to check your measurements in both metric and imperial units, then use our BMI calculator above to find your personal BMI and see how it compares to NHS guidance for your height.
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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 Weight Alone Isn't The Whole Picture
Your appropriate weight depends on more than just height. Muscle mass, bone density, age, and where your body stores fat all play important roles in assessing overall health. Two people at the same height and weight can have very different body compositions — one athletic with high muscle, one less active with higher body fat.
This is why the NHS also recommends measuring waist circumference alongside BMI. For men, a waist above 94cm (37in) increases health risk; above 102cm (40in) is high risk. For women, increased risk starts at 80cm (31.5in) and high risk at 88cm (34.5in). Talk to your GP about what appropriate weight means for you personally — they can consider your complete health picture.
- 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 calculate the healthy weight range for my height?
Calculate the lower end by multiplying your height in metres squared by 18.5, and the upper end by multiplying by 24.9. For example, at 1.7m tall: lower = 18.5 × 2.89 = 53.5kg; upper = 24.9 × 2.89 = 71.9kg. Use our free BMI calculator above to check instantly.
Is BMI accurate for muscular or athletic people?
No — BMI doesn't distinguish between muscle and fat, so athletic individuals may have a high BMI despite low body fat. If you're very muscular, discuss your weight with your GP rather than relying on BMI alone.
Do different ethnicities have different healthy weight ranges?
Yes. The NHS recommends lower BMI thresholds for South Asian, Chinese, Black African, and Black Caribbean adults due to higher cardiovascular and diabetes risk at lower BMI. Healthy BMI for these groups starts at 18.5 but tops out at 22.9 rather than 24.9.
What's the difference between overweight and obese according to NHS guidance?
Overweight is a BMI of 25.0–29.9, while obese is 30.0 and above. However, weight-related health risks vary individually. Your GP can assess your personal health risk based on weight, waist measurement, and medical history.
Should I aim for the lower or upper end of the healthy BMI range?
The entire 18.5–24.9 range is considered healthy by the NHS. Where within that range is appropriate depends on your individual circumstances, family history, and health markers. Your GP can advise what's best for you.
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.