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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Where to Measure Your Waist — Women's Guide
Measuring your waist accurately is one of the most important steps in assessing your health risk, especially when combined with your BMI. The NHS recommends measuring your waist circumference alongside weight to get a complete picture of your health. Unlike BMI alone, waist measurement directly indicates where fat is stored around your body — and excess abdominal fat carries particular health risks. This UK health guide shows you exactly where and how to measure, so you can track your waist accurately over time.
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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 Measure Your Waist — Step-by-Step
Accurate waist measurement requires finding the right location on your body. Stand upright and relaxed — do not suck in your stomach or tighten your core. Locate the soft area just above your hip bones (your natural waist) and just below your rib cage. Wrap a soft measuring tape around your waist at this midpoint, keeping it parallel to the floor and snug (but not tight). Measure at the end of a normal breath out — not when you have inhaled. Record the measurement to the nearest 0.5 cm. Repeat twice to check consistency.
Take your measurement in centimetres (cm) for NHS comparisons. If you prefer imperial, note that roughly 1 inch = 2.54 cm, so an 80 cm waist is approximately 31.5 inches.
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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.
What Your Waist Measurement Means — NHS Thresholds
The NHS provides clear guidance on healthy waist circumference for women:
- Under 80 cm (31.5 inches): Low health risk
- 80–88 cm (31.5–34.5 inches): Increased health risk
- Over 88 cm (34.5 inches): High health risk
These thresholds apply to women of most ethnic backgrounds. However, for women of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds: increased risk at 78 cm and high risk at 84 cm. Combined with your BMI, waist measurement gives your GP or healthcare professional a much clearer picture of your metabolic health and potential weight-related health risks.
- 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 alone does not show where fat is stored on your body. Excess fat around your abdomen (visceral fat) carries higher cardiovascular and metabolic risk than fat stored elsewhere. Measuring your waist alongside your BMI gives a more complete health picture. Use our free BMI calculator alongside waist measurement for a fuller assessment.
Should I measure my waist over clothing or against bare skin?
Measure against bare skin for accuracy, or wear light clothing only. Do not measure over bulky jumpers or tight clothes, as this distorts the reading. Measure at the same time of day for consistency — ideally in the morning before eating.
How often should I measure my waist?
Measure once a month to track changes over time. Waist circumference can change before weight on scales shifts, making it a useful early indicator of health progress. Our free progress tracker helps you log both weight and waist measurements together.
What if my waist is larger than NHS health thresholds?
Your GP can discuss lifestyle changes — diet and physical activity — to support gradual waist reduction. If you are overweight or obese, your GP may refer you to weight management services. Sustainable reduction of 0.5–1 kg per week often leads to waist circumference improvement.
Is waist-to-height ratio more accurate than waist measurement alone?
Yes, waist-to-height ratio is a strong predictor of health risk. Simply divide your waist circumference (cm) by your height (cm). A healthy ratio is below 0.5 for all adults. For example, a woman 165 cm tall with a healthy ratio would have a waist under 82.5 cm. ```
Ready to take control of your weight loss journey?
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