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 Does Weight to Ratio Mean for Your Health?
Weight to ratio refers to how your body weight relates to your height and other measurements — a key indicator of health risk. The most common ratio used in UK health guidance is waist-to-height ratio, which research shows is often more accurate than BMI alone for predicting cardiovascular health. Understanding your personal weight ratio helps you assess whether your weight sits in a healthy range according to NHS guidance, and whether you might benefit from lifestyle changes or talking to your GP about weight management options.
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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.
Key Weight Ratios Used in UK Health Assessment
Waist-to-height ratio is considered by many health professionals as a better predictor of health risk than BMI alone. A healthy waist-to-height ratio is below 0.5 for all adults — meaning your waist circumference should be less than half your height. For example, if you're 175cm tall, your waist should ideally be under 87.5cm.
- Formula: waist circumference ÷ height (in same units)
- Below 0.5 = lower health risk
- 0.5 to 0.6 = increased risk
- Above 0.6 = high health risk
BMI (Body Mass Index) remains the NHS standard screening tool. Use our free BMI calculator above to find your personal BMI, which indicates whether you're in the healthy weight range (18.5–24.9), overweight (25–29.9), or obese (30+). However, BMI has limitations — it doesn't distinguish between muscle and fat, so athletes may have a high BMI but low health risk.
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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.
How to Measure and Understand Your Personal Ratio
To calculate your waist-to-height ratio, measure your waist at the narrowest point (usually just above your hip bones) in centimetres. Measure your height in centimetres. Divide waist by height. Our free weight converter and BMI calculator on this page can help you understand your measurements in both metric and imperial units.
If your waist-to-height ratio is above 0.5, or your BMI falls in the overweight or obese range, speaking to your GP is a good first step. They can assess your individual health picture and discuss weight management options with you, which may include lifestyle changes, referral to NHS weight management services (tier 3), or — if appropriate — prescription weight loss support. Many UK adults find tracking their progress with a free progress tracker helpful when making health changes.
- 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 waist-to-height ratio and BMI?
BMI measures overall body weight relative to height, but doesn't account for muscle or fat distribution. Waist-to-height ratio focuses on abdominal fat specifically, which is linked to greater health risk. Research suggests waist-to-height ratio is often a better predictor of cardiovascular risk than BMI alone, though NHS uses BMI as its standard screening tool.
Is a waist-to-height ratio of 0.5 healthy?
Yes — a waist-to-height ratio below 0.5 is considered healthy for all UK adults. If your ratio is 0.5 or above, it indicates increased health risk and may be worth discussing with your GP. This threshold applies across all age groups and both sexes according to current research.
Can I improve my weight-to-ratio measurements?
Yes. Both waist-to-height ratio and BMI can improve through sustainable lifestyle changes including reduced-calorie diet, regular physical activity, and adequate sleep. Weight loss at 0.5–1 kg per week is the NHS-recommended safe rate. Your GP can advise on approaches suitable for you.
Do I need a prescription weight loss medication if my ratio is unhealthy?
Not necessarily. Your GP will assess your individual situation, including overall health and any weight-related conditions. Prescription weight loss medications like Mounjaro or Wegovy are available through NHS specialist services or private prescribing for eligible adults, but are always used alongside lifestyle changes, never instead of them.
What other health factors should I consider alongside my weight ratio?
Blood pressure, cholesterol levels, blood sugar control, family health history, and physical fitness all matter. Your GP can order blood tests and give you a full health picture. Weight is just one factor — overall health is multifactorial. Regular check-ups and honest conversations with your GP help you understand your personal health profile.
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.