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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Average Weight For Age — UK Data & Healthy Ranges
Average weight varies significantly by age, height, and individual factors. In the UK, the average adult man weighs approximately 85.7 kg (13st 7lbs) and the average adult woman weighs approximately 71.6 kg (11st 3lbs), according to Office for National Statistics data. However, "average" does not mean "healthy" — your ideal body weight depends on your height, frame size, and overall health. Use our free BMI calculator to find your personal healthy weight range based on NHS guidelines, which accounts for your unique measurements.
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 Group
Weight naturally increases during early adulthood, peaks in middle age (typically 45–65 years), and may decline slightly in older age due to muscle loss. ONS data shows:
- Adults aged 16–24: average 75–80 kg (11st 12lbs–12st 8lbs)
- Adults aged 25–34: average 80–85 kg (12st 8lbs–13st 5lbs)
- Adults aged 35–44: average 85–90 kg (13st 5lbs–14st 2lbs)
- Adults aged 45–54: average 87–92 kg (13st 9lbs–14st 6lbs)
- Adults aged 55–64: average 85–88 kg (13st 5lbs–13st 12lbs)
- Adults aged 65+: average 80–85 kg (12st 8lbs–13st 5lbs)
These are population averages only. Your healthy weight range depends on your height, not your age. Use our weight converter to check your weight in both kg and stone, then calculate your BMI to see where you fall within NHS healthy weight guidelines.
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.
Factors Affecting Ideal Weight & Healthy Weight Range
Ideal body weight varies between individuals due to several factors beyond age:
- Height: Taller individuals naturally weigh more. A healthy weight range for 5ft 6in is different from 6ft 2in.
- Muscle mass: Muscle is denser than fat. Athletes may have a higher BMI but still be very healthy.
- Frame size: Bone structure and frame size affect ideal weight. Small, medium, and large frames have different healthy weight ranges.
- Ethnicity: The NHS recommends lower BMI thresholds for South Asian, Chinese, Black African, and Black Caribbean adults due to higher cardiovascular risk at lower weights.
- Gender: Women typically weigh less than men at the same height due to body composition differences.
Rather than comparing yourself to age-based averages, calculate your personal healthy weight range using your height. The NHS recommends a healthy BMI of 18.5–24.9 for most adults.
- 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's the average weight for a 30-year-old woman in the UK?
Average weight for women aged 25–34 in the UK is approximately 71–75 kg (11st 3lbs–11st 11lbs) according to ONS data. However, this is just an average — your healthy weight depends on your height, not your age. Use our BMI calculator with your height to find your personal healthy weight range.
Is average weight the same as healthy weight?
No. Average weight is simply the mean weight of a population group. Healthy weight is defined by BMI relative to height, not age. The average person may be overweight, so a healthy weight range is more reliable than population averages. NHS guidelines recommend a BMI of 18.5–24.9 for adults.
What weight should I aim for at my age?
Rather than aiming for an age-based weight, calculate your healthy weight range using your height. For someone 1.70m tall, a healthy weight range is approximately 53–72 kg (8st 5lbs–11st 5lbs). Your GP or our free BMI calculator can help determine your personal healthy target.
Why do people weigh more as they get older?
Weight typically increases with age due to muscle loss (sarcopenia) being replaced by fat, changes in metabolism, and hormonal shifts. However, older adults don't need to weigh more — maintaining a healthy BMI remains important for health throughout life. Regular physical activity helps preserve muscle mass.
How do I convert my weight to stone to compare with average UK weight?
Use our free weight converter to instantly convert between kg and stone. For example, 75 kg equals 11st 11lbs. Once you know your weight in stone, use our BMI calculator with your height to see whether your weight falls within the NHS healthy weight range.
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.