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 Your Correct Weight? A UK Health Guide
There's no single "correct" weight that applies to everyone — your correct weight depends on your height, age, sex, muscle mass, and overall health. However, the NHS provides evidence-based guidance to help you find your healthy weight range. Using our free BMI calculator and weight converter, you can discover whether your current weight falls within a healthy range for your height and explore what healthy weight management means for you personally.
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.
How to Calculate Your Correct Weight Range
Your correct weight range is determined primarily by your height and BMI (Body Mass Index). The NHS defines a healthy BMI as between 18.5 and 24.9 for most adults, though lower thresholds apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage.
- To calculate your healthy weight range: Multiply your height in metres by itself, then multiply by 18.5 and 24.9. This gives your lower and upper healthy weight bounds.
- Example: For someone 1.75m tall, the healthy range is 56.6kg to 76.1kg (approximately 8st 12lbs to 11st 13lbs).
- Individual factors matter: Muscle mass, bone density, age, and medical conditions all affect what "correct" means for you personally.
- Use our weight converter: Convert between kg, stone, and lbs instantly to see your weight in familiar UK measurements.
Your GP can provide personalised guidance if you're unsure whether your current weight is healthy for your individual circumstances.
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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.
Beyond BMI — What Else Defines Your Correct Weight?
BMI is a useful screening tool but has important limitations — it doesn't distinguish between muscle and fat, so athletes may have a high BMI despite being fit. For a more complete picture, the NHS also recommends monitoring your waist circumference. A healthy waist measurement is under 94cm (37 inches) for men and under 80cm (31.5 inches) for women. Additionally, factors like your age, medications, family health history, and any existing health conditions influence what your correct weight should be. Rather than chasing a number on the scales, focus on sustainable habits: regular physical activity, balanced nutrition, and consistency. Our free progress tracker helps you log weight changes over time and 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.
What is the correct weight for my height?
Use the NHS BMI formula: aim for a BMI between 18.5–24.9 (or 18.5–22.9 if you're of South Asian, Chinese, Black African, or Black Caribbean heritage). Our free BMI calculator instantly shows your healthy weight range based on your exact height. For example, at 1.70m, the healthy range is approximately 53–72kg.
Does my correct weight change with age?
Your healthy BMI range stays the same throughout adulthood (18.5–24.9), but how your body distributes weight may change with age. Muscle naturally decreases and fat increases with ageing, so you may need to be more active to maintain the same weight. Your GP can advise on age-specific health targets.
Is there a correct weight if I have muscle or am very athletic?
If you're muscular, your BMI may be higher than "ideal" because muscle weighs more than fat. In this case, waist circumference and how you feel physically are better guides than BMI alone. Discuss your individual situation with your GP or a sports health professional.
How do I find my correct weight if I have a medical condition?
Medical conditions like thyroid disease, PCOS, and diabetes affect weight differently. Your GP or a registered dietitian can assess your correct weight range in the context of your specific health needs and any medications you take.
Can prescription weight loss medication help me reach my correct weight?
Medications like Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only treatments that may help some adults reach a healthier weight range. They require clinical assessment by a licensed prescriber and work alongside diet and activity changes. Use our GLP-1 weight loss calculator to explore potential outcomes.
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.