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 Chart — UK Health Reference
Understanding the relationship between age, weight, and height is essential for managing your health in the UK. While there's no single "ideal weight" that applies to everyone, the NHS provides clear guidance through BMI categories and healthy weight ranges based on height. Your age, height, and current weight together paint a picture of your health risk profile. This guide explains how these three factors work together, how to use our free BMI calculator to find your healthy weight range, and when to seek advice from your GP about weight management.
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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.
NHS Guidance on Weight, Height and Age
The NHS doesn't define separate weight targets by age — instead, it uses BMI (Body Mass Index) categories that apply consistently to adults aged 18 and over. A healthy BMI is 18.5 to 24.9 for most UK adults, based on height and weight regardless of age.
Why height matters more than age: Your height is the primary determinant of a healthy weight range. Two 55-year-old adults at different heights will have completely different healthy weight ranges. For example, a woman 1.63m tall should weigh between approximately 49–65 kg for a healthy BMI, whereas a man 1.83m tall should weigh between approximately 62–83 kg.
- South Asian, Chinese, Black African, and Black Caribbean adults: The NHS recommends lower BMI thresholds (18.5–22.9) due to higher cardiovascular risk at standard thresholds
- Older adults: Muscle mass naturally decreases with age, so BMI alone becomes less accurate in advanced age — your GP may consider other health markers
- Waist circumference matters: Where you carry weight is important at any age — men should aim for under 94cm, women under 80cm
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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.
Using Our Free BMI Calculator and Weight Converter
Rather than relying on generic age-based charts, use our free BMI calculator to find your personal healthy weight range based on your height. Simply enter your height in metres (or feet and inches) and current weight in kg or stone, and the calculator instantly shows your BMI category and healthy weight range for your height.
Our weight converter helps you switch between UK measurements (stone and pounds) and kilograms, making it easy to track progress. If your BMI falls outside the healthy range (18.5–24.9), your GP can provide personalised guidance on weight management, including lifestyle changes or, if appropriate, medical support such as prescription weight loss medication. Age, weight and height interact with your overall health picture — your GP knows your individual risk factors and can advise you best.
- 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 ideal weight for my age and height?
There is no single ideal weight based on age alone. The NHS uses BMI, which is calculated from your height and weight. A healthy BMI of 18.5–24.9 applies to all UK adults regardless of age. Use our BMI calculator to find your healthy weight range for your specific height.
Do weight and height requirements change as you get older?
BMI categories remain the same throughout adulthood, but older adults may have less muscle mass, making BMI less precise. Your GP can assess your individual health needs. Weight management remains important at all ages for reducing disease risk.
How accurate are weight-for-height charts compared to BMI?
BMI is the NHS-recommended standard for adults because it accounts for the relationship between weight and height mathematically. Generic charts can be helpful for context but don't personalise to your specific measurements as accurately as BMI does.
Should I aim to lose weight if I'm overweight but feel healthy?
Being overweight (BMI 25–29.9) increases risk of type 2 diabetes, heart disease, and other conditions even if you feel well. The NHS recommends discussing your weight with your GP, who can assess your individual health profile and advise whether weight loss would benefit you.
Where can I find NHS guidance on healthy weight management?
The NHS website provides free weight management resources including the NHS Weight Loss Plan, a 12-week programme. Your GP can refer you to local weight management services, and our free BMI calculator and weight converter help you track your measurements in UK units you're familiar with.
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.