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 Is The Correct Weight For Me?
There is no single "correct" weight for everyone — your ideal weight depends on your height, age, sex, muscle mass, and overall health. The NHS uses BMI (body mass index) as a screening tool to help determine if your weight falls within a healthy range for your height. However, the best weight for you is one that helps you feel healthy, energetic, and free from weight-related health conditions. Use our free BMI calculator above to find your personal healthy weight range, and speak with your GP if you have concerns about your weight and health.
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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 to Find Your Healthy Weight Range
The NHS defines a healthy weight as a BMI between 18.5 and 24.9 for most UK adults. Your healthy weight range depends entirely on your height. For example, at 5ft 6in (168cm), a healthy weight typically falls between approximately 50kg and 67kg (7st 12lbs to 10st 6lbs). For someone 5ft 10in (178cm), the healthy range is roughly 56kg to 75kg (8st 12lbs to 11st 11lbs).
Use our free weight converter to see what your current weight is in stone, lbs, or kg. Then calculate your BMI using our BMI calculator to see where you sit. If your BMI falls between 18.5 and 24.9, you're in the healthy range. Important: BMI has limitations — it doesn't account for muscle mass, so athletes or very muscular individuals may have a higher BMI but still be healthy. Your GP can give you personalised advice about what's right for your body.
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 That Affect Your "Correct" Weight
Your ideal weight isn't just about a number on the scales. Several factors influence what your correct weight should be: genetics (some people naturally carry weight differently), age (muscle mass naturally decreases with age), sex (men and women have different healthy BMI ranges), and ethnicity (the NHS recommends lower BMI thresholds for South Asian, Chinese, Black African, and Black Caribbean adults due to higher health risks at lower weights).
Additionally, if you have weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea, your GP may recommend a specific weight target to help manage these conditions. This is why speaking with your GP is the best way to establish your personal correct weight — they can assess your individual health picture, not just a number.
- 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 NHS healthy weight range for my height?
The NHS uses BMI to define healthy weight. For most adults, a BMI between 18.5 and 24.9 is healthy. Your specific weight range depends on your height — use our free BMI calculator to find yours. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends slightly lower thresholds (BMI 18.5–22.9). Always ask your GP for personalised advice.
Is my weight "correct" if my BMI is in the healthy range?
A healthy BMI is a good sign, but it's not the whole picture. BMI doesn't distinguish between muscle and fat, so athletes may have a higher BMI but still be very healthy. Other factors matter too — your waist circumference, how you feel, your energy levels, and any weight-related health conditions. Your GP can assess whether your current weight is right for your individual health.
Can my correct weight change over time?
Yes, absolutely. Your correct weight may change as you age (you may need to adjust it as muscle naturally decreases), if you develop health conditions, or if your lifestyle changes significantly. Regular check-ins with your GP help ensure your weight targets remain appropriate. Using our free progress tracker can help you monitor changes over time.
What if I'm significantly overweight — how do I work out my correct weight?
If your BMI is above 25, your GP can help you set a realistic, healthy weight target. Rather than aiming for a specific number immediately, aim to lose weight gradually (around 0.5–1kg per week is sustainable). Even a 5–10% reduction in body weight can bring significant health benefits. Your GP or a weight management service can support you with diet, exercise, and if appropriate, medication options.
Does my correct weight depend on my age?
Yes, it can. Whilst BMI categories remain the same regardless of age, the health risks associated with excess weight may increase with age. Additionally, muscle mass naturally decreases with age, which can affect how your weight is distributed. Older adults may need different approaches to weight management. Your GP can advise whether your weight is appropriate for your age and health status.
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.