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
Weight Chart With Age — Understanding Healthy Weight Ranges
A weight chart with age helps you understand what constitutes a healthy weight at different stages of life. However, it's important to know that the NHS doesn't recommend age-specific weight targets for adults. Instead, healthy weight is determined by BMI (body mass index), which applies equally across all adult ages. Your height, not your age, is the primary factor in calculating a healthy weight range. That said, understanding how weight patterns change with age can help inform your health management decisions.
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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 BMI Works Across All Ages
BMI is the standard measure used by the NHS for healthy weight across all adult ages. Rather than age-specific charts, the NHS uses universal BMI categories that apply whether you're 25 or 75. According to NHS guidance, a healthy BMI is between 18.5 and 24.9 for most adults. Your height is the key factor — not your age — in determining your healthy weight range. For example, a 5ft 8in (173cm) adult should weigh between approximately 55kg (8st 10lbs) and 74kg (11st 10lbs) to fall in the healthy BMI range. You can calculate your personal BMI instantly using our free BMI calculator above. For people of South Asian, Chinese, Black African, or Black Caribbean backgrounds, the NHS recommends slightly lower BMI thresholds, with a healthy range of 18.5 to 22.9.
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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.
Age and Weight Changes — What's Normal
While there isn't a "healthy weight chart by age", it's normal for weight to change across the lifespan. Most adults experience a gradual weight gain in their 30s and 40s, with metabolism naturally slowing by approximately 2–3% per decade after age 30. Weight can also increase during major life transitions — pregnancy, menopause, or after reducing physical activity due to injury or illness. However, these changes don't mean higher weight is "healthy" — they simply reflect life circumstances. Use our free weight converter to track your weight across different measurements (kg, stone, lbs), and monitor your progress with 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.
Is there an official weight chart based on age?
No. The NHS doesn't publish age-specific weight charts for adults. Instead, healthy weight is determined by BMI, which applies equally to all adults regardless of age. Your height is the primary factor, not your age. If you're concerned about your weight at any life stage, your GP can provide personalised guidance based on your individual health.
Why does weight naturally increase with age?
Metabolism slows by about 2–3% per decade after age 30, partly due to gradual muscle loss (sarcopenia) if physical activity decreases. Hormonal changes, especially in women during menopause, can also affect weight distribution. However, weight gain isn't inevitable — maintaining physical activity and muscle mass helps offset these changes.
How do I know my healthy weight if I'm older?
Use your BMI, which applies at any age. Our free BMI calculator shows your healthy weight range based on your height. If you have specific health conditions common in older age (diabetes, heart disease), your GP might recommend a weight target tailored to your individual needs — discuss this during your next appointment.
Is waist measurement important alongside weight and age?
Yes, waist circumference is actually more important than age. The NHS recommends measuring waist circumference as well as weight. For men, waist over 102cm indicates high health risk; for women, over 88cm. Weight alone doesn't tell the full story — where your body stores fat matters significantly.
Should older adults aim to lose weight differently?
Older adults can safely lose weight, but more slowly (0.25–0.5kg per week) to protect muscle mass. Strength training alongside reduced-calorie diet becomes more important with age. Always consult your GP before starting significant weight loss, especially if you take multiple medications or have existing health conditions.
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.