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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Work Out The Range — Your UK Healthy Weight Guide
Working out your healthy weight range is the first step towards understanding your personal health picture. In the UK, the NHS uses BMI (Body Mass Index) to calculate a healthy weight range based on your height, and this varies depending on your age, sex, and ethnic background. Whether you're checking your current weight status or planning weight management, knowing your target range gives you a realistic, personalised goal. This guide explains how to calculate your range using NHS standards and why it matters for your long-term health.
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.
How to Calculate Your Healthy Weight Range Using NHS Guidelines
The NHS healthy weight range is based on Body Mass Index (BMI), which measures the relationship between your weight and height. A healthy BMI falls between 18.5 and 24.9 kg/m² for most UK adults. To work out your personal healthy weight range, use the formula: healthy weight = BMI × height (in metres) squared. For example, if you're 1.73 metres tall (5ft 8in), your healthy weight range is approximately 55kg (8st 10lbs) to 74kg (11st 10lbs). However, if you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a lower threshold: BMI 18.5 to 22.9 is considered healthy for these groups, as they face higher health risks at lower BMI levels. Use our free BMI calculator above to instantly calculate your personal healthy range — simply enter your height and current weight, and the tool will show you exactly where you fall on the NHS scale and what your target range should be.
- Healthy BMI: 18.5–24.9 for most adults
- Lower thresholds: 18.5–22.9 for South Asian, Chinese, and Black African/Caribbean adults
- Ethnicity-adjusted ranges are evidence-based and supported by NHS guidance
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 Weight Range Matters — UK Health Context
Understanding your healthy weight range isn't about appearance — it's about reducing your risk of serious health conditions. Being overweight or obese significantly increases the risk of type 2 diabetes, heart disease, high blood pressure, certain cancers, and sleep apnoea. The NHS estimates that obesity costs the UK health system £6.5 billion annually. Even losing just 5–10% of your body weight can have meaningful health benefits: lower blood pressure, improved blood sugar control, better joint mobility, and reduced sleep apnoea symptoms. Your GP can help you set a realistic, personalised target within your healthy range based on your individual health profile, family history, and any existing health conditions. If you're unsure where to start, ask your GP for guidance — they can help you work towards your range through dietary changes, increased physical activity, or weight management support programmes available on the NHS.
- 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 if my healthy weight range seems very wide?
Healthy weight ranges are intentionally broad because they account for natural variation in muscle mass, bone density, and frame size. Two people with identical height and BMI can look very different. The range gives you flexibility — aim for wherever you feel healthiest and most energetic within that range. Your GP can help you identify a more specific target based on your health history.
Does the healthy weight range change if I'm very muscular?
Yes. BMI doesn't distinguish between muscle and fat, so very muscular individuals (including athletes) may have a high BMI but low body fat. In these cases, your GP may recommend additional measurements like waist circumference or body composition assessment rather than relying on BMI alone. Use our weight converter to check your weight in different units, then discuss results with your GP.
How quickly should I aim to reach my healthy weight range?
The NHS recommends losing weight at a rate of 0.5–1 kg (1–2 lbs) per week for sustainable results. This typically requires a calorie deficit of around 500 kcal per day. Faster weight loss is possible but increases the risk of muscle loss and nutritional deficiencies. A gradual approach is more likely to result in lasting lifestyle changes.
What if I'm already in my healthy weight range but still feel unwell?
Weight is only one factor in overall health. Being in a healthy BMI range doesn't assures perfect health — other factors like fitness level, diet quality, stress, sleep, and genetics all matter. If you feel unwell, speak with your GP, who can investigate other possible causes and provide personalised advice.
Can I use an online calculator, or do I need to see my GP?
Online calculators like our free BMI calculator are excellent starting points for understanding your health picture and are backed by NHS standards. However, they provide general information only — your GP can assess your individual circumstances, discuss any health risks specific to you, and recommend the best approach for reaching your healthy range, including weight management programmes or other support available on the NHS.
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.