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 Weight for Your Height?
Your ideal weight depends on your height, age, and body composition. In the UK, the NHS uses BMI (Body Mass Index) to determine whether weight falls within a healthy range for a given height. Rather than a single "ideal" weight, there's actually a healthy weight range for each height. Use our free BMI calculator above to find where your current weight sits, and discover what healthy weight means for you specifically.
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.
NHS Weight Ranges by Height
The NHS defines healthy weight as a BMI between 18.5 and 24.9. This translates to different weight ranges depending on your height. For example, at 5ft 6in (168cm), a healthy weight range is roughly 51–68kg (8st 1lb to 10st 10lb). At 5ft 10in (178cm), the healthy range is approximately 56–76kg (8st 12lb to 12st). For South Asian, Chinese, Black African, or Black Caribbean adults, the NHS recommends lower thresholds — a healthy BMI starts at 18.5 but extends only to 22.9, reflecting higher health risks at standard BMI levels for these populations. Individual needs vary based on muscle mass, bone density, and overall health. Your GP can provide personalised guidance for your specific circumstances.
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.
Tools to Help You Find Your Healthy Weight
Rather than targeting a single number, focus on achieving a weight that puts you in the healthy BMI range for your height. Use our free weight converter to check what your current weight means in stone and kilograms. Our free BMI calculator above instantly shows where your weight sits against NHS guidelines. If you're working towards weight loss, track your progress using our free progress tracker. Remember: sustainable healthy weight is achieved through balanced nutrition, regular physical activity, and consistency — not rapid changes. Your GP can discuss what a healthy weight target looks like for you personally.
- 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 healthy weight range for someone 5ft 5in tall?
At 5ft 5in (165cm), a healthy BMI (18.5–24.9) equals roughly 49–66kg (7st 10lb to 10st 5lb). Use our BMI calculator above with your exact weight to see where you sit. Your individual healthy weight depends on muscle mass and overall fitness, so discuss targets with your GP.
Does healthy weight change with age?
BMI categories remain the same across adulthood, but muscle naturally decreases with age whilst fat increases. This means you may need to maintain a slightly lower weight in later years to stay healthy. The NHS recommends regular health checks to monitor weight and health markers as you age.
Why is my healthy weight different from my friend's at the same height?
Height is just one factor. Healthy weight also depends on muscle mass, bone density, genetics, age, sex, and medical history. Two people of identical height and weight can have very different body compositions. This is why BMI has limitations and why personalised GP advice is valuable.
How do I know if I need to lose weight?
Check your BMI using our free calculator on this page. If your BMI is 25–29.9, you're in the overweight range; 30+, you're in the obese range. However, BMI alone doesn't tell the full story. Discuss your health with your GP, who can assess your overall fitness, health markers, and whether weight loss would benefit you.
What's the safest way to reach a healthy weight?
The NHS recommends losing 0.5–1kg per week through a combination of balanced eating and physical activity. Crash diets rarely work long-term. If you're struggling, your GP can refer you to NHS weight management services or discuss options including GLP-1 medications if appropriate for your health profile.
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.