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
Average Weight Per Age — What's Healthy?
Average weight varies significantly by age, height, and individual factors — there's no single "ideal" number that applies to everyone. What matters more is whether your weight falls within a healthy BMI range (18.5 to 24.9 according to NHS guidelines) for your specific height. This guide explains average UK weight by age and how to determine if your personal weight is healthy using the BMI framework, plus how to calculate your ideal weight range in both kg and stone.
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.
Average UK Weight by Age and Healthy BMI Ranges
Average UK adult weights (based on ONS data) are approximately 85.7 kg (13 stone 7 lbs) for men and 71.6 kg (11 stone 3 lbs) for women. However, these are population averages — not targets. A healthier approach is to calculate your ideal weight range based on your height and BMI.
For a healthy BMI of 18.5–24.9, your weight range depends entirely on height. For example, someone 5ft 6in (168 cm) tall should weigh between approximately 53–70 kg (8 stone 5 lbs to 11 stone) for a healthy BMI. Someone 6ft (183 cm) tall would have a healthy range of 61–82 kg (9 stone 8 lbs to 12 stone 13 lbs).
Age alone doesn't change BMI categories — but muscle mass naturally decreases with age, meaning older adults may need to be more mindful of weight maintenance. Using our free BMI calculator above, you can find your personalised healthy weight range instantly by entering your height and current weight.
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.
How to Find Your Ideal Weight Using BMI
Your ideal body weight isn't about a number on the scale — it's about achieving a healthy BMI for your height. The NHS defines a healthy weight range as BMI 18.5–24.9 for most adults; however, for South Asian, Chinese, Black African, and Black Caribbean adults, the range is 18.5–22.9 due to higher health risks at higher BMI levels.
To calculate your ideal weight range: multiply 18.5 by your height in metres squared for the lower bound, and 24.9 by the same figure for the upper bound. Convert the result to stone using our weight converter if you prefer imperial measurements. Your GP can also discuss what a healthy weight means specifically for you, taking into account your health conditions, fitness level, and personal circumstances.
- 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 average weight for a UK adult?
According to ONS data, the average UK adult man weighs approximately 85.7 kg (13 stone 7 lbs) and the average woman weighs 71.6 kg (11 stone 3 lbs). However, average doesn't mean healthy — your personal ideal weight depends on your height and BMI, not on population averages.
Does age affect what a healthy weight should be?
Age doesn't change BMI categories, but it does affect body composition. Muscle naturally decreases with age, so older adults may need to prioritise strength training alongside weight management. A healthy BMI of 18.5–24.9 applies across all adult ages.
How do I calculate my ideal weight range?
Use the BMI formula: multiply 18.5 by your height in metres squared for the lower bound, and 24.9 for the upper bound. For example, at 1.68m tall, a healthy weight is 52–70 kg (8 stone 2 lbs to 11 stone). Use our free BMI calculator above to find your range instantly.
Is there a different healthy weight range for different ethnicities?
Yes. NHS guidelines recommend lower BMI thresholds for South Asian, Chinese, Black African, and Black Caribbean adults (18.5–22.9 instead of 18.5–24.9), as these groups face higher cardiovascular and diabetes risks at higher BMI levels.
What should I do if my weight is outside the healthy range?
If your BMI is outside 18.5–24.9, speak to your GP. Even a modest 5–clinically studied weight loss can improve health outcomes. Your GP can discuss lifestyle changes, weight loss support programmes, and whether prescription weight loss treatment might be suitable for your circumstances.
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.