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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What's Your Ideal Weight by Age and Height?
Your ideal weight depends on your height, age, frame size, and muscle mass — not just a single number. The NHS uses BMI (body mass index) to define healthy weight ranges, which apply across all adults regardless of age. For most UK adults, a healthy BMI sits between 18.5 and 24.9, though lower thresholds apply to people of South Asian, Chinese, Black African, or Black Caribbean heritage. This guide explains ideal body weight ranges for different heights, why age matters less than you might think, and how to find your personal healthy weight target using NHS-aligned data.
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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.
Healthy Weight Ranges by Height (UK Data)
The NHS defines a healthy weight range based on height alone, not age. Here are ideal weight ranges for common UK heights, using both metric and imperial measurements:
- 5ft (152cm): 47–64 kg (7st 4lbs–10st)
- 5ft 4in (163cm): 54–73 kg (8st 6lbs–11st 7lbs)
- 5ft 6in (168cm): 58–79 kg (9st 2lbs–12st 6lbs)
- 5ft 8in (173cm): 62–84 kg (9st 10lbs–13st 3lbs)
- 5ft 10in (178cm): 66–89 kg (10st 4lbs–14st)
- 6ft (183cm): 71–96 kg (11st 2lbs–15st 2lbs)
These ranges represent a BMI of 18.5–24.9, which the NHS considers healthy for adult populations. Use our free BMI calculator above to find your exact healthy weight range for your 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.
Factors That Affect Your Ideal Weight
Ideal weight is not one-size-fits-all. Several factors influence what constitutes a healthy weight for you personally:
- Muscle mass: Muscle weighs more than fat, so athletes and people with higher muscle mass may have a higher ideal weight than BMI alone suggests
- Frame size: Larger-framed individuals naturally weigh more than small-framed people of the same height
- Age: Metabolic rate decreases slightly with age, but healthy BMI ranges remain the same across all adult ages
- Ethnicity: The NHS recommends lower BMI thresholds (18.5–22.9) for South Asian and other high-risk populations due to greater cardiovascular disease risk at lower weights
Consult your GP for personalised guidance about your ideal weight target based on your individual health profile.
- 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.
Does ideal weight change with age?
No — the NHS healthy BMI range (18.5–24.9) applies to all adults regardless of age. However, maintaining a healthy weight becomes increasingly important with age, as excess weight raises the risk of age-related conditions like type 2 diabetes and cardiovascular disease. Metabolic rate does decrease slightly with age, meaning you may need fewer calories to maintain the same weight.
What's the difference between ideal weight and average weight in the UK?
Ideal weight is your healthy target range based on height and BMI guidelines. Average UK weight is what people actually weigh — currently around 85.7kg for men and 71.6kg for women. The average UK adult exceeds the healthy weight range, which is why many adults are classified as overweight or obese by NHS standards. These are different measures.
How do I calculate my healthy weight range?
Use the formula: healthy weight in kg = BMI (18.5–24.9) × height in metres squared. For example, at 1.73m (5ft 8in), your healthy range is 55–74kg (8st 9lbs–11st 9lbs). Our free BMI calculator above calculates this instantly — just enter your height and get your exact healthy weight range for UK adults.
Why do South Asian and Black African adults have different ideal weight thresholds?
Research shows these populations have higher risk of type 2 diabetes and heart disease at lower BMI levels. The NHS therefore recommends a healthy BMI of 18.5–22.9 for South Asian, Chinese, Black African, and Black Caribbean adults — lower than the standard 18.5–24.9 range. This personalised approach better reflects individual health risk factors.
Does muscle mass change what my ideal weight should be?
Yes. BMI doesn't distinguish muscle from fat. An athlete with significant muscle mass may have a "high" BMI but low body fat and excellent health. Conversely, someone with "normal" BMI but low muscle mass may have high body fat. For a complete picture, combine BMI assessment with waist circumference measurement (over 94cm for men and 80cm for women indicates increased health risk).
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.