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
Healthy Weight Loss: Understanding Your BMI and Ideal Weight Range
Healthy weight loss means losing weight at a sustainable pace whilst achieving a BMI within the NHS healthy range of 18.5 to 24.9. Rather than crash dieting, evidence shows that losing 0.5 to 1 kg per week alongside gradual lifestyle changes produces the best long-term results. Your ideal body weight depends on your height, age, and individual health factors — not just a number on the scales. The NHS healthy weight framework uses BMI as a screening tool to help you understand whether your current weight puts you at increased health risk. Let our free BMI calculator help you find your personal healthy weight range today.
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.
BMI-Based Healthy Weight Ranges for UK Adults
The NHS defines a healthy BMI as 18.5 to 24.9 for most UK adults. This translates to a specific weight range that depends entirely on your height. For example, at 5ft 8in (173cm), a healthy weight range is approximately 55.4 to 74.5 kg (8st 10lbs to 11st 10lbs). At 5ft 4in (163cm), the range is roughly 49.2 to 66 kg (7st 10lbs to 10st 5lbs).
However, if you are of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds: a healthy BMI range of 18.5 to 22.9. These groups face higher health risks at the same BMI due to genetic and metabolic factors.
- BMI 18.5–24.9: Healthy weight (standard populations)
- BMI 18.5–22.9: Healthy weight (South Asian and Black African/Caribbean populations)
- BMI 25–29.9: Overweight — increased health risk
- BMI 30+: Obese — substantially increased health risk
Use our free BMI calculator above to find your exact healthy weight range based on your height and ethnicity.
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.
Achieving Healthy Weight Loss: Practical Steps
Sustainable healthy weight loss requires a calorie deficit of roughly 500 kcal per day, which typically results in losing 0.5 kg per week. The NHS recommends never losing more than 1 kg per week without medical supervision, as faster loss increases muscle loss and nutritional deficiency risk.
Combine dietary changes — such as reducing portion sizes, eating more vegetables and protein, and limiting sugary drinks — with increased physical activity. Walking, swimming, and strength training all support healthy weight loss. Many people benefit from tracking their progress: our free progress tracker helps you log weight changes and identify patterns over time. Consider consulting your GP if you have underlying health conditions, take medication, or have struggled with weight loss previously.
- 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 healthy BMI range for UK adults?
The NHS defines a healthy BMI as 18.5 to 24.9 for most UK adults. For South Asian, Chinese, Black African, and Black Caribbean adults, the NHS recommends a lower healthy range of 18.5 to 22.9 due to higher health risks at the same BMI. Your GP can advise on the healthy range most relevant to you.
How much weight should I lose per week for healthy results?
The NHS recommends losing 0.5 to 1 kg (1 to 2 lbs) per week for sustainable, healthy weight loss. This typically requires a daily calorie deficit of around 500 kcal. Faster weight loss may result in muscle loss and is generally not recommended without medical supervision.
How do I calculate my healthy weight range?
Your healthy weight range depends on your height and BMI. A healthy BMI of 18.5–24.9 multiplied by your height squared (in metres) gives your weight range in kilograms. Use our free BMI calculator above — it calculates your personalised healthy weight range instantly based on your height.
Does my ethnicity affect my healthy weight range?
Yes. The NHS recognises that South Asian, Chinese, Black African, and Black Caribbean populations face higher health risks at lower BMIs. If you belong to these groups, your healthy BMI range may start at 18.5–22.9 rather than 18.5–24.9. Always discuss your personal healthy weight with your GP.
What is the difference between BMI and ideal body weight?
BMI is a screening tool using height and weight to estimate health risk. Ideal body weight is a theoretical range based on various formulas, but BMI provides the NHS standard for UK adults. BMI doesn't distinguish between muscle and fat, so it's a useful starting point alongside waist measurement and GP consultation.
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.