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 Much Should I Weigh? Find Your Healthy Weight Range
There's no single "right" weight for everyone — it depends on your height, age, sex, and body composition. The most practical way to find out if you're in a healthy weight range is to calculate your BMI (Body Mass Index) using your height and weight. Use our free BMI calculator above to find your personal healthy weight range instantly, based on NHS guidelines. This guide explains what those results mean and what to do next.
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.
What Does the BMI Calculator Tell You?
The BMI calculator works by comparing your weight to your height, giving a single number that helps determine whether you're in a healthy weight range according to NHS guidelines. Here's how to interpret the result:
- BMI 18.5–24.9: Healthy weight range — this is the target zone for most UK adults.
- BMI 25–29.9: Overweight — still relatively healthy, but increased risk of weight-related health conditions.
- BMI 30 and above: Obese — higher health risks. Your GP may recommend weight management support.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends slightly lower thresholds — a healthy BMI is 18.5–22.9 instead of 24.9, because these groups face higher cardiovascular and diabetes risk at the same BMI. Calculate your personal BMI now using the calculator on this page to see exactly where you fall and what your healthy weight range is for your specific height.
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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.
What If You're Above the Healthy Weight Range?
If your BMI falls above the healthy range, you're not alone — around 63% of UK adults are overweight or obese. The good news is that even modest weight loss (5–10% of your current weight) can bring real health benefits, including lower blood pressure, better blood sugar control, and reduced joint strain.
Your next step depends on your situation: speak to your GP, who can assess your individual health and discuss options with you. These may include lifestyle changes (diet and exercise), referral to an NHS weight management service, or in some cases, prescription support. Use our free weight converter to track your progress in stone, pounds, or kilograms — whichever measurement feels easiest for you to monitor.
- 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 a healthy weight for my height in the UK?
A healthy weight range depends on your height and body composition. Use our free BMI calculator to find your personal healthy weight range in stone, pounds, or kilograms. Generally, a BMI between 18.5 and 24.9 is considered healthy by NHS guidelines, but lower thresholds apply for certain ethnic groups.
Is BMI the only way to know if my weight is healthy?
BMI is a useful screening tool, but it has limitations — it doesn't distinguish between muscle and fat, so athletes may have a high BMI but low body fat. Your GP can also consider your waist circumference, blood pressure, blood sugar, and overall health history for a complete picture.
What's the difference between overweight and obese on the BMI scale?
According to NHS guidelines, overweight is a BMI of 25–29.9, and obese is 30 and above. Class I obesity is 30–34.9, Class II is 35–39.9, and Class III (severe obesity) is 40 and above. Each category carries increasing health risks, but treatment options are available at every stage.
Can I lose weight safely at home, or do I need to see my GP?
Modest weight loss through diet and exercise (0.5–1 kg per week) can be done safely at home. However, it's always wise to tell your GP, especially if you have health conditions or take medications. For gradual weight management or if you're significantly above a healthy weight, medical support is recommended.
How quickly should I expect to lose weight?
NHS guidance recommends losing 0.5–1 kg (1–2 lbs) per week for sustainable weight loss. This typically requires a calorie deficit of around 500 calories per day. Faster loss is possible but may involve muscle loss. Use our free progress tracker to monitor your weight loss journey over time.
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.