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 Compute Weight in the UK
Computing your weight means understanding what your current weight means for your health and how it compares to healthy ranges recommended by the NHS. Whether you want to convert between kg, stone, and pounds, calculate your BMI, or track weight loss progress, this guide covers everything you need to know about weight assessment in the UK. Understanding your weight is the first step towards better health management.
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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 Calculate and Assess Your Weight
There are several ways to compute and assess your weight effectively in the UK. The most common approach is using BMI (Body Mass Index), which relates your weight to your height to indicate whether you're in a healthy range according to NHS guidance. For UK adults, a healthy BMI is between 18.5 and 24.9. You can calculate BMI using this formula: weight (kg) ÷ height (m)². Our free BMI calculator on this page does this instantly — simply enter your weight and height.
- Weight conversion: UK adults often use stone and pounds, so converting between kg, stone, and lbs is essential. 1 kg equals 0.157 stone, or 2.2 pounds. Our weight converter above lets you switch between these measurements instantly.
- Healthy weight range: To find your healthy weight range for your height, multiply your height (m) squared by 18.5 and 24.9. For example, at 5ft 8in (1.73m), a healthy weight is approximately 55–75 kg (8st 10lbs to 11st 10lbs).
- Ethnicity considerations: If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, NHS guidance recommends lower BMI thresholds — healthy weight starts at BMI 18.5 and overweight begins at 23.
Regular weight monitoring is part of good weight management. Track your weight weekly on the same day, at the same time, ideally in the morning before eating.
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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.
NHS Guidance and Using MyWeightCheck Tools
The NHS provides clear weight management guidance for UK adults. If your BMI falls outside the healthy range, your GP can discuss weight management strategies with you, which might include lifestyle changes, referral to a specialist service, or in some cases, prescription weight loss treatment. MyWeightCheck offers free tools to help you compute and understand your weight. Use our free BMI calculator to check your current BMI instantly, our weight converter to move between kg, stone, and pounds easily, and our GLP-1 weight loss calculator if you're exploring weight management options. If you're concerned about your weight or health, always consult your GP for personalised advice.
- 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 easiest way to compute my weight in the UK?
The easiest method is using our free BMI calculator on this page — enter your weight in kg or stone and your height, and it instantly calculates your BMI and compares it to NHS healthy ranges. You can also use our weight converter to switch between kg, stone, and pounds. Both tools are free and give you immediate results without any calculations needed on your part.
How do I know if my computed weight is healthy?
Compare your BMI to NHS guidelines. A healthy BMI is 18.5–24.9 for most UK adults, or 18.5–22.9 if you're of South Asian, Chinese, Black African, or Black Caribbean heritage. You can also calculate your healthy weight range for your height — multiply your height (m) squared by 18.5 and 24.9. If you're uncertain, your GP can give you personalised guidance based on your individual health.
Should I compute my weight in kg or stone?
In the UK, both kg and stone are commonly used. The NHS uses kg for clinical records, but many UK adults prefer stone and pounds for everyday use. Our weight converter lets you switch between both instantly, so you can use whichever measurement you find clearer. Choose the one that helps you track your progress most effectively.
How often should I compute and check my weight?
Weighing yourself once a week is ideal for tracking trends without becoming obsessive. Weigh yourself on the same day and time each week, preferably in the morning before eating or drinking. Your weight naturally fluctuates daily due to water retention, food, and hormones, so weekly tracking smooths out these variations and shows real progress over time.
What should I do if my computed weight is outside the healthy range?
Start by discussing it with your GP, who can assess your individual health and recommend personalised next steps. This might include lifestyle changes, a referral to an NHS weight management service, or other support. Weight management is complex and involves genetics, medical history, and environment — your GP can help you create a realistic, healthy plan tailored to your needs.
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.