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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Age Height Weight Scale — UK Health Guide
A healthy weight depends on your age, height, and individual health factors rather than a single number on the scales. In the UK, the NHS uses BMI (Body Mass Index) alongside other measurements like waist circumference to assess whether your weight is healthy for your height. Understanding where your weight sits relative to NHS guidelines helps you make informed decisions about your health. This guide explains how age, height, and weight relate to one another and how to use these metrics sensibly for weight management.
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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.
NHS Weight Guidelines by Height and Age
The NHS does not provide separate weight scales for different ages in adults — instead, it uses BMI categories that apply equally to all adults aged 18 and over, regardless of age. This is because BMI itself accounts for the relationship between your weight and height. However, body composition changes naturally with age: muscle mass typically decreases and fat mass increases, which is why two people of the same height and weight may have different levels of fitness.
Healthy weight ranges by height (for adults):
- 5ft 0in (152cm): 47–64kg (7st 5lbs–10st 0lbs)
- 5ft 4in (163cm): 54–73kg (8st 6lbs–11st 7lbs)
- 5ft 8in (173cm): 61–82kg (9st 8lbs–12st 12lbs)
- 5ft 10in (178cm): 64–87kg (10st 1lbs–13st 10lbs)
- 6ft 0in (183cm): 71–96kg (11st 2lbs–15st 1lbs)
These ranges assume a BMI between 18.5–24.9. Remember that weight alone doesn't determine health — use our free BMI calculator above to find your personal healthy weight range based on your exact height.
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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, Weight and Health — What Really Matters
Rather than following a strict weight target, the NHS recommends focusing on sustainable lifestyle changes: regular physical activity, a balanced diet, and monitoring your waist circumference alongside weight. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds because these groups face higher cardiovascular and diabetes risk at lower weights — healthy BMI for these groups begins at 18.5 and overweight starts at 23.0 rather than 25.0.
Your GP can provide personalised guidance on a healthy weight for you personally. If you're concerned about your weight or how it relates to your age and health, speak to your GP rather than relying on age-based scales alone. Our free weight converter makes it easy to check your weight in stone, pounds, or kilograms.
- 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 healthy weight change as you get older?
Healthy weight ranges (BMI 18.5–24.9) don't officially change with age in the NHS system. However, body composition naturally changes — you typically lose muscle and gain fat as you age, even at the same weight. This is why regular physical activity and strength training become increasingly important. Your GP can advise on healthy weight targets for your individual circumstances.
What's the difference between weight and BMI?
Weight is simply the number on the scales. BMI combines your weight with your height to give a more meaningful health picture. Two people weighing 70kg might have very different BMIs if they're different heights. BMI has limitations though — it doesn't distinguish between muscle and fat. Use our free BMI calculator above to find your personal BMI and healthy weight range.
Why do UK health guidelines mention ethnicity and weight?
Research shows that people of South Asian, Chinese, Black African, and Black Caribbean heritage have higher risk of type 2 diabetes and heart disease at lower BMI levels than other populations. The NHS therefore recommends lower weight thresholds for these groups — overweight starts at BMI 23.0 instead of 25.0. This reflects genuine health differences, not arbitrary discrimination.
Should I aim for a specific weight or a weight range?
Aim for a range rather than a single target number. A healthy weight range for your height is typically 3–5kg wide. Focusing on a range reduces obsessive weighing and accounts for normal daily fluctuations. More importantly, focus on how you feel, your energy levels, and your health markers (blood pressure, cholesterol, blood sugar) rather than the scales alone.
How can I find my healthy weight for my height?
Use our free BMI calculator at the top of this page — enter your age, height, and current weight to see whether you fall into the NHS healthy range. You can also use our weight converter to see your weight in stone, pounds, or kilograms. For personalised advice, your GP is the best source — they understand your full health picture and any conditions that might affect your ideal weight.
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.