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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Age Weight and Height Scale — Finding Your Healthy Range
Understanding what a healthy weight should be at your age and height can help you assess your overall health. In the UK, the NHS uses BMI (body mass index) as the primary screening tool, combined with age, height, and weight to determine whether you fall within a healthy range. However, health is complex — age, height, genetics, muscle mass, and individual circumstances all play a role. This guide explains how age, weight, and height relate to health, and how to use UK health metrics to find your personal healthy weight range.
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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 Age, Weight, and Height Affect Health
Age matters because body composition changes over time. Younger adults typically have more muscle mass, while older adults may have less muscle and more body fat at the same weight. The NHS BMI categories remain the same across all ages for adults (18+), but your GP may consider additional factors if you are very elderly or have specific health conditions.
Height determines what weight is healthy for you. Two people weighing 75kg will have very different BMI values if one is 160cm tall and the other is 180cm tall. This is why height is essential when assessing weight health. Use our free weight converter to switch between kg, stone, and pounds, then check your BMI using the calculator on this page.
- Healthy BMI range (NHS): 18.5 to 24.9
- Overweight range: 25.0 to 29.9
- Obese range: 30.0 and above
- For South Asian, Chinese, Black African, and Black Caribbean adults, lower thresholds apply (18.5–22.9 for healthy weight)
Clinically BackedWeight Loss
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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.
Creating a Healthy Weight and Height Scale for Your Age
Rather than thinking of a rigid "scale" by age, the NHS recommends calculating your personal healthy weight range based on your height alone. For example, at 170cm tall (5ft 7in), a healthy weight ranges from approximately 53kg to 72kg. At 180cm (5ft 11in), the healthy range is 60kg to 81kg. Your age doesn't change these ranges for adults, but it may influence how your GP advises you on weight management.
If you're concerned about whether your current weight is healthy for your age and height, your GP can provide personalised advice. They may also recommend weight management support, lifestyle changes, or assessment for conditions like type 2 diabetes or high blood pressure that are linked to excess weight. Track your progress using our free progress tracker to monitor changes 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.
What is a healthy weight for my height?
A healthy weight depends on your height and is determined using BMI. For example, at 170cm, healthy weights range from 53kg to 72kg (BMI 18.5–24.9). Use our free BMI calculator on this page to find your personal healthy weight range by entering your height and weight instantly.
Does age affect what a healthy weight should be?
For adults aged 18+, the NHS BMI categories don't change with age. However, your GP may consider your age when advising on weight management, as muscle mass naturally decreases with age. Body composition matters more than weight alone.
How do I know if I'm overweight for my height and age?
Calculate your BMI using your height and current weight. If your BMI is 25–29.9, you're in the overweight range. If it's 30+, you're in the obese range. BMI is a screening tool — your GP can assess whether your weight poses a health risk for you personally.
What's the difference between weight, height, and BMI?
Weight is what you weigh in kg or stone. Height is how tall you are. BMI combines both to indicate whether your weight is healthy for your height. BMI = weight (kg) ÷ height (m)². Our free BMI calculator above works this out instantly.
Should I lose weight if my BMI is above 25?
If your BMI is above 25, your GP can advise whether weight loss is appropriate for you. This depends on your age, health conditions, fitness, and family history — not BMI alone. Even a 5–clinically studied weight loss can improve health outcomes. Consult your GP for personalised guidance.
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.