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
17 x 40 — UK Health Context & Weight Management
The measurement 17 x 40 most commonly refers to waist and hip circumference in centimetres, which is relevant for assessing health risk according to NHS guidance. Waist circumference is a key indicator of whether excess weight is concentrated around your abdomen, which carries higher health risks than weight distributed elsewhere. According to NHS health advice, waist measurement is as important as BMI when evaluating cardiovascular health. Our free weight converter and BMI calculator can help you understand your current measurements in UK context and determine whether your healthy weight range aligns with NHS recommendations for adults.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Waist Circumference & Health Risk Assessment
Waist circumference is measured around the smallest part of your waist, midway between your lowest rib and hip bone. A waist measurement of 40cm (approximately 15.75 inches) falls well within the healthy range for UK adults, though context matters significantly.
- Women: waist over 80cm = increased cardiovascular risk; over 88cm = high risk
- Men: waist over 94cm = increased risk; over 102cm = high risk
- A 40cm waist measurement is healthy for most adults and indicates low abdominal fat accumulation
- Waist-to-height ratio below 0.5 is considered healthy for all adults
The NHS recommends monitoring both waist measurement and BMI together, as this combination provides better health risk assessment than either measure alone. Weight management that reduces waist circumference can significantly lower your risk of type 2 diabetes, cardiovascular disease, and certain cancers.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Using Measurements for Health Monitoring
If you're monitoring your health using body measurements, our free weight converter helps you understand readings in UK measurements (stone, pounds, and kilograms). Track changes over time rather than focusing on single measurements, as gradual reductions indicate successful weight management.
For personalised nhs health advice about your measurements and what they mean for your individual health, speak with your GP. They can assess your complete health picture, including blood pressure, blood sugar levels, and family history. A healthy weight uk range varies by height, age, and ethnicity — the NHS provides specific guidance for different populations, particularly for adults of South Asian, Chinese, Black African, or Black Caribbean heritage who may have different health risk thresholds.
- 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 does a 40cm waist measurement indicate for health?
A 40cm waist is healthy for most UK adults and indicates low abdominal fat. According to NHS guidelines, increased cardiovascular risk for men begins around 94cm, so 40cm is well within a healthy range. However, your overall health depends on multiple factors including BMI, blood pressure, and fitness level.
How do I measure my waist correctly?
Stand upright and measure horizontally around your waist at the midpoint between your lowest rib and hip bone, keeping the tape measure snug but not tight. Measure after breathing out naturally. Take the measurement at the same location each time for accurate tracking and consistent healthy weight uk monitoring.
Is waist measurement more important than BMI?
Both measurements matter. BMI screens for overall weight status, while waist circumference indicates where fat is stored — abdominal fat carries higher health risks. The NHS recommends assessing both together for a complete picture of your health status.
What's the connection between waist measurement and weight management?
Reducing waist circumference through weight management indicates you're losing visceral fat (deep abdominal fat), which is linked to serious health conditions. Even a 5–10% reduction in body weight can significantly improve waist measurement and cardiovascular health markers.
Should I use a different waist measurement target if I'm of South Asian descent?
Yes. The NHS recommends slightly lower waist measurement thresholds for adults of South Asian, Black African, and Black Caribbean heritage due to higher metabolic health risks at similar measurements compared to white British adults. Consult your GP for personalised nhs guidance based on your ethnicity.
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.