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 As Per Age Chart — UK Health Guidance
There isn't a single "correct" weight for a given age in the UK — healthy weight depends on your height, not your age. The NHS uses Body Mass Index (BMI) to determine healthy weight ranges, which apply equally to adults of all ages. This guide explains how to find your healthy weight range using UK health standards, and how our free BMI calculator can help you assess whether your current weight falls within a healthy range for your height.
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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.
How UK Health Services Assess Healthy Weight
The NHS does not publish age-specific weight charts for adults because healthy weight is determined by height, not age. Instead, the NHS uses BMI (Body Mass Index) as the primary screening tool for healthy weight across all adult ages.
- A healthy BMI is between 18.5 and 24.9 for most UK adults
- For South Asian, Chinese, Black African, or Black Caribbean adults, the NHS recommends a healthy BMI of 18.5 to 22.9 due to higher cardiovascular risk at lower BMI levels
- BMI is calculated as weight (kg) ÷ height (m)² — it applies to adults aged 18 and over equally
Age itself does not change what a healthy weight should be, though age-related changes in muscle mass, metabolism, and physical activity can affect how easy or difficult it is to maintain a healthy weight. Our free BMI calculator above can instantly show you whether your weight is in the healthy range for your height.
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 Weight Management Tools and NHS Resources
Rather than relying on age-based weight charts, the NHS recommends using your height and current weight to calculate your BMI. You can then cross-reference this with NHS BMI categories to understand your weight status.
If you're concerned about your weight regardless of age, your GP can:
- Assess your individual health risk factors
- Discuss lifestyle changes, physical activity, and nutrition
- Refer you to specialist weight management services if appropriate
- Explore prescription weight management options if eligible
Use our free weight converter to switch between kg, stone, and lbs — this makes it easier to track your weight in the units you prefer. Many UK adults find it helpful to track weight changes over time using our progress tracker to spot trends.
- 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 ideal weight for my age in the UK?
No. The NHS does not use age-specific weight targets for adults. Instead, healthy weight is determined by your height and BMI. All adults — whether 25 or 75 — use the same BMI categories (18.5–24.9 for healthy weight). Age may affect your metabolism or activity level, but your healthy weight range is based on height, not age.
How do I find my healthy weight range using NHS guidance?
Calculate your BMI using your weight and height. A healthy BMI is 18.5–24.9 for most UK adults (18.5–22.9 for South Asian or Black African heritage). Our BMI calculator above does this instantly. You can also calculate the healthy weight range for your height using the formula: healthy weight = 18.5 to 24.9 × your height in metres squared.
Does age affect how much weight I should aim to lose?
Age itself doesn't determine weight loss targets — your current BMI and health conditions do. However, older adults may benefit from slower, more gradual weight loss to preserve muscle mass. Your GP can advise you on a safe rate of weight loss tailored to your age, health, and circumstances.
What should I do if I'm unsure whether my weight is healthy?
Start by calculating your BMI using our free BMI calculator. If your BMI falls outside the healthy range (18.5–24.9), or if you have weight-related health concerns, speak to your GP. They can assess your individual health risk factors and discuss weight management options appropriate for you.
Are children and teenagers assessed using the same weight charts as adults?
No. Children use age and sex-specific growth centile charts (UK90 reference), not adult BMI categories. If you're concerned about a child's weight, speak to your GP or health visitor. The NHS Healthy Weight Calculator has a separate tool for children.
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.