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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What is Your Ideal Weight? A UK Health Guide
Your ideal weight is the healthy weight range that's right for your individual height and body type. In the UK, "ideal" is defined by BMI — specifically a BMI between 18.5 and 24.9, which the NHS recognises as a healthy weight range for most adults. However, your ideal body weight isn't a single number; it's a range that accounts for individual differences in muscle, bone density, and frame size. This guide explains how to find your personalised healthy weight range and why BMI provides a practical framework for understanding what healthy weight means for you.
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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 BMI Defines Healthy Weight Range
The NHS healthy weight range is based on body mass index (BMI), a measurement calculated from your height and weight. A healthy BMI falls between 18.5 and 24.9 kg/m². To find your specific healthy weight range for your height, multiply your height in metres squared by 18.5 and 24.9 — this gives your lower and upper healthy weight boundaries.
For example, an adult who is 1.73m tall (5ft 8in) has a healthy weight range of approximately 55kg to 74kg (8st 10lbs to 11st 10lbs). Use our free BMI calculator above to instantly calculate your personal healthy weight range based on your exact height — the calculator translates results into both kg and stone, making it easy to understand in UK measurements.
It's important to note that healthy weight for height varies significantly between individuals. Two people of the same height may have different ideal weights depending on muscle mass, bone density, and overall body composition. Your GP can provide personalised guidance on what healthy weight means for your specific circumstances.
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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.
Understanding Individual Ideal Weight Variation
The concept of "ideal weight" has evolved beyond a single target number. Rather than aiming for one specific weight, the NHS encourages people to work towards a healthy weight range that fits their body type and health status. Average UK weight is higher than the healthy range for most heights — current data shows the average UK adult weighs around 82kg (12st 12lbs) — but average is not the same as healthy or ideal.
Your ideal weight depends on factors including age, muscle mass, bone structure, and any existing health conditions. Some people feel their best at the lower end of the healthy BMI range; others thrive at the higher end. The key is finding a sustainable weight where you feel energised and your health markers (blood pressure, blood sugar, cholesterol) improve. A weight loss calculator can help you project realistic outcomes if you're aiming to reach your healthy range.
If you're currently above your healthy weight range and interested in reaching it, remember that even a 5–10% reduction in your current weight can bring significant health benefits. The NHS recommends losing weight gradually — approximately 0.5 to 1kg per week — to ensure sustainable, lasting change. Track your progress using our free progress tracker, which helps you log weight changes over time and see patterns in your journey. Your GP can also offer support, including referrals to specialist weight management services if needed.
- 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 is the difference between average weight and ideal weight?
Average weight is what most people actually weigh; ideal weight is the healthy range recommended by the NHS based on BMI. Average UK adult weight is around 82kg, but the healthy BMI range is 18.5–24.9, which typically corresponds to lower weights. Ideal weight is health-based; average weight is statistical.
How do I calculate my healthy weight range for my height?
Multiply your height in metres squared by 18.5 (lower bound) and 24.9 (upper bound). For example, at 1.75m tall: 18.5 × (1.75)² = 56.6kg and 24.9 × (1.75)² = 76.2kg. Use our free BMI calculator above for instant, accurate results in both kg and stone.
Is there one ideal weight for everyone at my height?
No. Ideal weight varies between individuals depending on muscle mass, bone density, age, and body composition. Two people of the same height can have different ideal weights. Your GP can help determine what's healthy and sustainable for your specific body and circumstances.
What if I'm above my healthy weight range — how do I reach my ideal weight?
Aim to lose weight gradually at 0.5–1kg per week through a combination of reduced-calorie diet and increased physical activity. The NHS offers free support through its weight loss plan and tier 3 specialist services. Your GP can discuss options including referrals to weight management programmes.
Does ideal weight apply differently to different ethnic groups?
Yes. The NHS recommends lower BMI thresholds for people of South Asian, Chinese, Black African, and Black Caribbean heritage, as these groups face higher health risks at the same BMI. A healthy BMI for these groups starts at 18.5–22.9 rather than 18.5–24.9.
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.