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 My Recommended Weight?
Your recommended weight depends on your height, age, muscle mass, and overall health — not just a single number. The NHS uses BMI (body mass index) as the primary health screening tool to determine if a weight is healthy for your height. A healthy BMI is between 18.5 and 24.9, though these thresholds vary for people of South Asian, Chinese, Black African, and Black Caribbean backgrounds. Your GP can give you personalised guidance based on your individual circumstances. Use our free BMI calculator above to find your personal BMI and healthy weight range instantly.
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.
NHS Healthy Weight Range by Height
Rather than one "ideal" weight, the NHS defines a healthy weight range for each height using BMI thresholds. For example, at 5ft 8in (173cm), a healthy weight is approximately 8st 6lbs to 11st 5lbs (54–72kg). At 5ft 4in (163cm), it's roughly 7st 6lbs to 10st 1lbs (48–64kg).
Your recommended weight within that range depends on:
- Muscle mass (athletes may weigh more but be very healthy)
- Bone density and frame size
- Age and metabolism
- Overall fitness and activity level
- Existing health conditions
Use our weight converter to switch between kg, stone, and pounds, then use our BMI calculator to find where your weight sits relative to NHS healthy thresholds for your height.
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.
When Weight Management Might Be Recommended
Your GP may discuss weight management if your BMI is 25 or above (overweight category) or if you have weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. The NHS recommends gradual, sustainable weight loss of 0.5–1kg (1–2lbs) per week through dietary changes and increased physical activity.
For some adults, prescription weight loss medication may be considered alongside lifestyle changes. These are available through NHS specialist weight management services or private prescribing following a clinical assessment. Track your progress using our free progress tracker if you're working towards a healthier weight.
- 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 weight range for someone 5ft 6in tall?
At 5ft 6in (168cm), a healthy BMI range gives a weight of approximately 7st 13lbs to 10st 10lbs (50–68kg). However, your ideal weight within this range depends on your muscle mass, frame size, and overall health. Your GP can advise on what's right for you individually.
Does recommended weight change with age?
BMI thresholds remain the same across adulthood, but your metabolism, muscle mass, and activity levels naturally change with age. Older adults may have different health needs. Discuss any concerns about your weight and health with your GP, who can provide age-appropriate guidance.
Why does the NHS use BMI instead of a single ideal weight?
BMI is a practical screening tool that accounts for your height. However, it doesn't distinguish between muscle and fat, so it has limitations. For a complete picture, your GP may also consider waist circumference, fitness level, and medical history alongside your BMI.
Is my recommended weight different if I'm South Asian or Black British?
Yes. The NHS recommends lower BMI thresholds for people of South Asian, Chinese, Black African, and Black Caribbean backgrounds because these groups face higher health risks at lower BMI levels. A healthy BMI for these groups is 18.5–22.9 instead of 18.5–24.9.
Where can I get personalised weight advice?
Your GP is the best source for personalised weight guidance based on your health history, medical conditions, and circumstances. They can refer you to NHS weight management services if appropriate, or discuss whether lifestyle changes, dietary support, or other interventions would benefit you.
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.