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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How to Measure Your Waistline — A UK Health Guide
Your waistline measurement is an important health indicator that your GP may assess alongside your BMI. Unlike BMI alone, waist measurement directly indicates where fat is stored around your abdomen, which is linked to increased risk of heart disease, type 2 diabetes, and other health conditions. Learning how to measure your waistline accurately using NHS guidance ensures you have reliable health data. This simple measurement takes just a minute and provides valuable information about your personal health status.
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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 Measure Your Waistline Accurately
Follow these NHS-recommended steps to measure your waist correctly:
- Stand upright and relax — do not suck in your stomach or tense your abdominal muscles
- Locate the top of your hip bone (iliac crest) by placing your hands on your hips
- Find the bottom of your rib cage by feeling along your ribs
- Measure halfway between these two points — this is your natural waist line
- Wrap a soft measuring tape (cloth tape, not metal) around your waist at this point
- Keep the tape snug but not tight — you should be able to slide one finger underneath
- Take the measurement at the end of a normal breath out
- Record the measurement in centimetres (cm)
- Repeat the measurement 2–3 times to ensure accuracy
- Take the average of your measurements
Measure your waist at the same time of day (preferably morning) for consistency, as measurements can vary by up to 2–3cm depending on what you have eaten or drunk.
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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.
UK Health Ranges and What Your Measurement Means
The NHS provides clear waist circumference thresholds for increased health risk:
- Men: 94cm (37 inches) = increased risk; 102cm (40 inches) = high risk
- Women: 80cm (31.5 inches) = increased risk; 88cm (34.5 inches) = high risk
These thresholds apply to adults of white European background. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — typically 5–8cm less — because these groups face higher cardiovascular and diabetes risk at the same waist measurements. A healthy waist-to-height ratio (your waist divided by your height, both in the same units) should be below 0.5 for all adults. Use our free BMI calculator alongside this measurement for a complete picture of your weight management and UK health context.
- 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.
Why is waist measurement important if I already know my BMI?
BMI does not distinguish between muscle and fat, and it does not show where fat is stored. Abdominal fat (around your organs) carries higher health risk than fat stored elsewhere. Two people with the same BMI but different waist measurements may have different health risks. The NHS recommends using both measurements together for a more complete assessment.
How often should I measure my waistline?
Measure your waist once a month, always at the same time of day and using the same measuring technique, to track changes accurately. Weekly measurements are not necessary and can be discouraging due to natural day-to-day fluctuations. Monthly measurements help you see real progress over time.
What if my waist measurement is above the NHS healthy range?
If your measurement exceeds the NHS thresholds, speak to your GP. They can assess your overall health, discuss your weight management options, and check for underlying conditions like high blood pressure or type 2 diabetes. Your GP may refer you to NHS weight management services or suggest lifestyle changes. Many people successfully reduce their waist measurement through diet and physical activity.
Is a cloth measuring tape better than a metal one?
Yes. Cloth measuring tape is more accurate because it sits flush against your skin, whereas metal tapes can curve and give inconsistent readings. Metal tapes are also more likely to slip. A soft cloth tape (usually found in haberdashery shops or online) costs just a few pounds and lasts for years.
Does the waist-to-height ratio work for all adults?
The waist-to-height ratio of below 0.5 is recommended for all adults regardless of ethnicity or background, making it a useful universal screening tool. However, always discuss your personal measurements with your GP, as they can assess your individual health context, family history, and any existing health conditions that may affect your risk 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.