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
What Is Your Perfect Weight?
Your "perfect weight" isn't a single number — it's a healthy weight range based on your height, age, and individual health. The NHS defines this using BMI (body mass index), which applies differently depending on your ethnic background. This guide explains how to find your healthy weight range, why BMI matters, and what steps you can take to achieve sustainable weight management for your personal health goals.
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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 Your Healthy Weight Range
Your healthy weight depends on your height and BMI category. The NHS recommends a BMI between 18.5 and 24.9 for most UK adults, though lower thresholds apply to people of South Asian, Chinese, Black African, or Black Caribbean heritage.
- Healthy BMI range: 18.5–24.9 (or 18.5–22.9 for South Asian and other specified groups)
- To calculate: Divide your weight in kg by your height in metres squared, or use our free BMI calculator above for gradual improvement
- Example: For someone 1.70m tall, a healthy weight range is approximately 53–72 kg (8st 5lbs to 11st 4lbs)
Your weight converter can quickly switch between kg, stone, and pounds so you see your weight in whichever units feel most natural.
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.
Why Your Perfect Weight Is Individual
Perfect weight varies because muscle weighs more than fat, bone density differs, and age affects metabolism. Two people at the same weight can look completely different. The NHS uses weight management guidance rather than one-size-fits-all targets because health is more important than a specific number on the scale.
Factors that influence your ideal weight include genetic background, fitness level, medical conditions, and medications. This is why your GP is the best person to advise you on what weight range is right for you. Even losing 5–10% of your current body weight can significantly improve health markers like blood pressure and blood sugar levels.
If you're working towards a healthier weight, tracking progress beyond just the scale can help — weight loss progress tracker tools let you log measurements, energy levels, and other improvements. Sustainable weight management combines realistic goals, consistent small changes to diet and activity, and regular health check-ins with your GP.
- 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 NHS healthy weight range?
The NHS recommends a BMI of 18.5–24.9 for most UK adults. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, a BMI of 18.5–22.9 is recommended due to higher health risks at higher BMI levels. Use our BMI calculator to check where you fall.
How do I calculate my perfect weight for my height?
Multiply your height in metres by itself, then divide your weight in kg by that number. Alternatively, our free BMI calculator does this instantly. For a healthy weight, aim for a BMI between 18.5 and 24.9, adjusting if you're from a higher-risk ethnic background.
Is there one perfect weight for everyone?
No. Perfect weight varies by height, age, muscle mass, genetics, and individual health conditions. Two people can be the same weight but look and feel completely different. Your GP can help you set a realistic, healthy target weight based on your circumstances.
What if I'm struggling to reach my healthy weight?
Sustainable weight loss of 0.5–1 kg per week is recommended. If you're finding it difficult, speak to your GP about support options, including structured diet programmes, behaviour change support, or in some cases, prescription weight management options alongside lifestyle changes.
Does my weight matter if I feel healthy?
Weight does matter for long-term health — excess weight increases risks of type 2 diabetes, heart disease, and certain cancers, even if you feel fine now. Regular health check-ups with your GP help identify any health risks early, regardless of how you feel.
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.