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 Ideal Weight According To Height And Age?
Your ideal weight depends primarily on your height, not your age. The NHS defines ideal body weight as a BMI between 18.5 and 24.9 — a range that applies to all adults regardless of age, though muscle loss with ageing may affect how weight distributes. Rather than a single "perfect" number, think of your ideal weight as a healthy range based on your height and individual body composition. Age itself doesn't change what's healthy; instead, staying active and maintaining muscle becomes more important as you get older. Use our free BMI calculator above to discover your personal healthy weight range instantly.
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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 Range By Height Using BMI
Your healthy weight range is calculated using your height and BMI. According to NHS guidelines, a healthy BMI sits between 18.5 and 24.9. To find your ideal weight range, multiply your height in metres by itself, then multiply by 18.5 (lower limit) and 24.9 (upper limit).
Example for 5ft 8in (1.73m):
- Lower healthy weight: 18.5 × 1.73² = 55.4 kg (8st 10lbs)
- Upper healthy weight: 24.9 × 1.73² = 74.5 kg (11st 10lbs)
- Healthy range: 55–75 kg (8st 10lbs to 11st 10lbs)
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends slightly lower thresholds: a healthy BMI of 18.5–22.9. This is because these groups face higher health risks at standard weight thresholds. Your GP can discuss whether adjusted targets are appropriate for you. Use the weight converter on this page to check these ranges in your preferred units — kg, stone, or pounds.
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.
Using Your Healthy Weight Range Effectively
Knowing your healthy weight range is a starting point, not a rigid target. Individual ideal body weight varies based on muscle mass, bone density, and personal health history — two people at the same height and weight can have very different body compositions. Rather than fixating on a single number, focus on the range and how you feel physically: energy levels, fitness improvements, and health markers like blood pressure and cholesterol often matter more than the scales.
Our BMI calculator above instantly shows your current BMI and healthy weight range for your height. If you're aiming to reach a healthier weight, track your progress using our free progress tracker to monitor not just weight changes, but also fitness gains and how your clothes fit over time.
- 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 age affect your ideal weight?
Age doesn't change the healthy BMI range (18.5–24.9), which applies to all adults. However, the way weight distributes can change with age due to natural muscle loss. Staying active and maintaining muscle becomes increasingly important with age to preserve strength and metabolism. Your GP can give personalised guidance if you have age-related health concerns.
What's the difference between ideal weight and average UK weight?
Average UK weight is simply what most adults currently weigh — approximately 85.7 kg for men and 71.6 kg for women. Ideal weight is what the NHS defines as healthy based on height and BMI. Many UK adults weigh more than the ideal range, which is why focusing on your personal healthy weight range matters more than comparing yourself to averages.
Can I use a simple chart to find my ideal weight?
Yes — our BMI calculator above generates a personalised healthy weight range in seconds. Alternatively, NHS resources provide weight-for-height charts. However, charts give approximate ranges, not perfect targets, because muscle mass and body composition vary between individuals. Your GP can discuss what's realistic and healthy for you.
Should I try to reach the exact middle of my healthy weight range?
No — anywhere within your healthy BMI range (18.5–24.9) is considered healthy. The middle isn't necessarily "ideal" for you. Some people feel best at the lower end, others at the upper end, depending on muscle mass and how they feel. Focus on sustainable habits rather than a specific number on the scales.
What if I'm significantly above or below my healthy weight range?
If you're above your healthy range, even losing 5–10% of body weight can improve health outcomes like blood pressure and blood sugar. If you're below, your GP may want to explore why. Either way, speak to your GP, especially if you're struggling with weight or have health concerns. They can discuss realistic goals and whether support like structured programmes or medication might help.
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.