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
What's a Healthy Target Weight For Your Height and Age?
Your target weight depends primarily on your height and age, and there's no single "perfect" number — health is more individual than that. The NHS recommends using BMI as a screening tool: a healthy BMI range is 18.5 to 24.9 for most UK adults, though this shifts slightly with ethnicity and age. Your GP can advise on a realistic, sustainable target based on your personal health, medical history, and fitness level. Even modest weight loss of 5–10% can deliver meaningful health improvements. Use our free BMI calculator above to find your healthy weight range instantly based on your specific measurements.
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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.
Healthy Weight Ranges By Height (NHS Framework)
The NHS uses BMI to define healthy weight rather than age-specific targets. A healthy BMI is 18.5–24.9 for most UK adults. Your target weight range depends entirely on your height — not your age (though metabolism does slow with age, requiring slightly fewer calories).
- At 5ft 4in (163cm): healthy weight is approximately 50–65kg (7st 12lbs to 10st 3lbs)
- At 5ft 8in (173cm): healthy weight is approximately 55–74kg (8st 8lbs to 11st 9lbs)
- At 5ft 10in (178cm): healthy weight is approximately 58–79kg (9st 1lbs to 12st 5lbs)
- At 6ft 0in (183cm): healthy weight is approximately 62–84kg (9st 11lbs to 13st 3lbs)
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — a healthy BMI starts at 18.5 and caps at 22.9. Use our free weight converter and BMI calculator to check your personal range.
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.
Why Age Isn't Your Primary Guide — And What Actually Matters
Unlike children (who have age-specific growth charts), healthy weight in adults isn't age-dependent — it's determined by height, body composition, and health status. However, age does affect your calorie needs. Adults over 50 typically need 100–200 fewer calories daily than younger adults, due to natural muscle loss. This means your target weight might stay the same but maintaining it requires adjustments to diet and activity. Weight management becomes more important with age because excess weight increases risk of type 2 diabetes, cardiovascular disease, and mobility problems — all factors your GP will consider when setting a realistic target with you.
- 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 a different target weight for older adults?
No — healthy weight ranges (BMI 18.5–24.9) remain the same regardless of age. However, older adults may need fewer calories to maintain their weight and benefit from strength training to preserve muscle. Your GP can advise on a target weight suited to your individual health.
How do I calculate my target weight range?
Use our free BMI calculator above — it instantly calculates your healthy weight range based on your height. Healthy BMI is 18.5–24.9, which translates to a range of several kilograms. For example, at 5ft 8in, the healthy range is roughly 55–74kg (8st 8lbs to 11st 9lbs).
Should I aim for the lower or upper end of my healthy weight range?
Either end is healthy. Your target should depend on your fitness level, muscle mass, how you feel, and your GP's advice — not a specific number. Many people are healthiest at the upper end of the range if they're muscular or very active.
Does my age affect how quickly I should lose weight?
The NHS recommends a safe rate of 0.5–1kg per week for all adults, regardless of age. Older adults should prioritise sustainable, gradual loss to protect muscle mass. Your GP can advise on an appropriate rate for you.
What if I have a medical condition — does that change my target weight?
Yes — certain conditions like type 2 diabetes or arthritis may mean your GP recommends a different target than standard BMI ranges. Always discuss your personal target with your GP rather than using BMI alone, especially if you have existing health conditions.
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.