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
Age, Height and Weight Chart — What's Healthy for You?
There's no single "ideal" weight for your age and height — healthy weight depends on your individual body composition, muscle mass, and overall health. However, the NHS uses BMI (body mass index) as a screening tool to determine whether a weight falls within a healthy range for a given height. This guide explains how age, height, and weight interact, and how to use free tools to find your personal healthy weight range. Use our free BMI calculator above to check your status instantly, or our weight converter to switch between kg, stone, and lbs.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
How BMI Works Across Different Ages and Heights
BMI is calculated the same way regardless of age — it's weight (kg) divided by height (m) squared. The NHS healthy weight range is a BMI of 18.5 to 24.9 for most adults. However, what this means in actual kilograms or stone depends entirely on your height.
- At 5ft 4in (163cm), a healthy weight range is approximately 46–65kg (7st 3lbs to 10st 3lbs)
- At 5ft 8in (173cm), a healthy weight range is approximately 55–75kg (8st 8lbs to 11st 10lbs)
- At 6ft (183cm), a healthy weight range is approximately 65–90kg (10st 3lbs to 14st 2lbs)
For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — healthy weight starts at BMI 18.5 but extends only to 22.9. Age itself does not change the healthy BMI range, though older adults may benefit from slightly higher body weight for bone health.
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 the Right Tool for Your Health
Rather than relying on age-specific charts, the NHS guidance is to calculate your individual BMI using your actual height and weight. Our free BMI calculator on this page instantly shows you where you fall — whether you're in the healthy range, overweight, or obese — and calculates your personal healthy weight range based on your exact height.
Remember that BMI has limitations: it doesn't account for muscle mass, so athletes may have a high BMI but low body fat. Waist circumference also matters — the NHS recommends men keep their waist below 94cm (37in) and women below 80cm (31.5in) for cardiovascular health. If you're concerned about your weight or health, your GP can offer personalised UK health advice beyond any chart.
- 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 what a healthy weight should be?
Age doesn't change the BMI formula or healthy range (18.5–24.9), but older adults may benefit from slightly higher body weight to protect bone density and muscle. Your GP can advise on what's healthy for your individual situation. Use our BMI calculator to find your personal healthy weight range based on your height.
What's the difference between weight charts by age and BMI?
Age-specific weight charts are often outdated and less accurate than BMI. The NHS now recommends BMI as the standard screening tool because it accounts for height. BMI stays the same calculation across all ages — only your height matters. Our weight converter and BMI calculator make it easy to check your status.
Can I use a weight chart if I'm very muscular or athletic?
BMI-based charts aren't ideal for athletes or very muscular people because they don't distinguish muscle from fat. If you're athletic, discuss your weight with your GP. Body composition measures like waist-to-hip ratio or body fat percentage may be more useful for you than BMI alone.
What if I'm below the healthy weight range on the chart?
A BMI below 18.5 is classified as underweight. This can increase risks of nutritional deficiency, weak bones, and weakened immunity. Speak to your GP if you're struggling to maintain a healthy weight — they can rule out underlying health conditions and offer support.
How do I track progress if I'm trying to lose or gain weight?
Use our free progress tracker to log your weight over time and see trends — single weigh-ins can vary. Combine this with our weight converter to track in your preferred unit (kg, stone, or lbs). Aim for steady progress of 0.5–1kg per week if losing weight, as recommended by the NHS.
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.