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
How to Compare Weight and Understand Your Health
Comparing weight isn't just about numbers — it's about understanding what those numbers mean for your health. Whether you're tracking your own weight, comparing yourself to NHS healthy weight guidelines, or converting between stone, kilograms, and pounds, context matters. This guide explains how to compare weight meaningfully using UK health standards, BMI thresholds, and evidence-based metrics that actually relate to your wellbeing.
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.
Different Ways to Compare Your Weight
Weight comparison takes several forms, and each tells you something different about health. Unit conversion (stone to kg, for example) is the simplest — our free weight converter lets you switch between metric and imperial instantly. BMI comparison is more useful: your weight in context of your height. Use our free BMI calculator to find your personal BMI and see where it falls on the NHS healthy weight scale (18.5 to 24.9 is healthy for most UK adults; lower thresholds apply if you're of South Asian, Chinese, Black African, or Black Caribbean heritage). Historical comparison tracks your own weight over time — our free progress tracker logs weekly or monthly changes so you can spot trends, not just daily fluctuations. Waist circumference matters too: a healthy waist is under 94cm for men and 80cm for women (higher risk over 102cm and 88cm respectively).
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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 Simple Number Comparison Can Mislead
Comparing raw weight numbers without context creates confusion. Two people weighing 80kg might have completely different health profiles depending on height, muscle mass, age, and genetics. Muscle weighs more than fat, so an athlete at 80kg may be healthier than someone else at the same weight with higher body fat. Weight fluctuates daily by 1–2kg due to hydration, food intake, and hormones — comparing day-to-day numbers is meaningless. Age and gender matter: healthy weight ranges differ. This is why NHS weight management guidance focuses on BMI, waist circumference, and your individual health conditions — not just the number on the scales. Always consult your GP if you're unsure whether your weight is healthy for you.
- 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 healthy weight in the UK and other countries?
The UK uses NHS guidelines with BMI 18.5–24.9 as healthy weight for most adults; those of South Asian or Black African heritage have lower thresholds (18.5–22.9) due to higher cardiovascular risk at lower BMI levels. The US uses identical BMI bands but different health context. Always use UK NHS guidance for your own health decisions.
How do I compare my weight to the average UK adult weight?
Average UK adult men weigh around 85.7kg (13st 7lbs); women around 71.6kg (11st 3lbs). However, "average" doesn't mean "healthy" — many UK adults are overweight or obese. Use our BMI calculator to compare yourself to NHS healthy weight ranges instead, which are based on height and health evidence.
Can I compare weight between stone and kilograms easily?
Yes. One stone equals 6.35kg exactly. Use our free weight converter above to switch instantly between stone, pounds, and kilograms. For example, 70kg equals 11 stone 0.1 pounds. This is useful for understanding your weight across different measurement systems.
Should I compare my weight now to my weight 10 years ago?
Weight changes over decades are normal due to age, lifestyle, and metabolism shifts. Rather than comparing to an old number, focus on current health metrics: your BMI, waist circumference, energy levels, and how you feel. Our progress tracker helps you monitor recent trends meaningfully over weeks and months.
What if I'm comparing weight loss progress on medication like Mounjaro or Wegovy?
Clinical trials show Mounjaro may help people lose around 15–21% of body weight on average, while Wegovy averaged clinically studied weight loss — but individual results vary significantly. Use our GLP-1 weight loss calculator to estimate your potential weight loss at different doses. Always track progress with your prescriber, not just the scales.
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.