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 Calculate Your Weight in UK Measurements
Calculating your weight and understanding what it means for your health is the first step towards better weight management. Whether you need to convert between kilograms, stone, and pounds, or want to know how your weight relates to your health, MyWeightCheck provides free tools and clear guidance aligned with NHS standards. Our weight converter and BMI calculator make it simple to assess your current weight and find your healthy weight range for your height and age.
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.
Calculate Weight Using Our Free Tools
The easiest way to calculate your weight is using our free weight converter and BMI calculator above. Simply enter your current weight in any unit (kilograms, stone, or pounds) and the tools instantly convert it and show you where you fall on the NHS health scale.
- Weight converter: Convert between kg, stone, and pounds — essential for understanding UK health guidance, which often mixes metric and imperial measurements
- BMI calculator: Calculate your BMI instantly to see if your weight falls within the healthy range (18.5–24.9) according to NHS standards
- Healthy weight range: For your height, calculate the upper and lower healthy weight bounds using NHS BMI categories
For most UK adults, a healthy weight falls between BMI 18.5 and 24.9. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds (18.5–22.9), as these groups face higher health risks at the same BMI.
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.
Understanding Your Weight and Health Context
Calculating your weight is only part of the picture. The NHS also considers waist circumference, which can indicate health risk even if your BMI is normal. Men should aim for a waist below 94cm (37 inches); women below 80cm (31.5 inches).
If you're overweight or obese according to NHS categories, even modest weight loss of 5–10% can improve blood pressure, blood sugar control, and reduce cardiovascular risk. A GP can give you personalised advice about your individual weight and any health conditions that might benefit from weight management support.
Whether through lifestyle changes, structured diet programmes, or in some cases prescription weight management support, achieving a healthier weight is possible with the right approach and professional guidance.
- 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.
How do I calculate my weight in stone from kilograms?
Divide your weight in kilograms by 6.35. For example, 70kg ÷ 6.35 = 11 stone (approximately). Our free weight converter above calculates this instantly. Most UK adults prefer stone and pounds, so you can also convert the remaining kilograms to pounds for the exact figure.
What is a healthy weight according to NHS guidance?
A healthy weight is one that gives you a BMI between 18.5 and 24.9. However, healthy weight varies by height. Use our free BMI calculator to find your personal healthy weight range. For adults of South Asian or Black African heritage, the NHS recommends a BMI of 18.5–22.9 instead.
Can I calculate my weight loss potential if I'm considering weight management medication?
Yes. Our free GLP-1 weight loss calculator can help you estimate potential results based on clinical trial data from medications like Mounjaro and Wegovy. These show average weight loss of 15–21% of body weight, though individual results vary significantly and require a clinical assessment.
How often should I calculate and track my weight?
The NHS recommends weighing yourself once weekly at the same time of day for accurate tracking. Our free progress tracker helps you log weekly weights and visualise your weight loss journey over time. Daily weigh-ins can be misleading due to natural water and food weight fluctuations.
Does calculating my BMI tell me everything about my health?
BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat, so athletes may have a high BMI despite low body fat. Your GP should also consider waist circumference, family history, and any weight-related health conditions when assessing your overall health risk.
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.