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 an Overweight BMI?
An overweight BMI ranges from 25.0 to 29.9 according to NHS guidelines. If your BMI falls in this range, it means your weight is above the healthy threshold for your height, but below the obese category. However, BMI is just one measure of health — it doesn't account for muscle mass, fitness level, or where fat is distributed on your body. Your GP can help you understand what your individual BMI means for your health and whether any action is needed.
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 BMI Ranges and Overweight Category
The NHS BMI formula is simple: divide your weight in kilograms by your height in metres squared. According to the NHS bmi categories uk standard, an overweight BMI sits between 25.0 and 29.9.
- Healthy BMI: 18.5–24.9
- Overweight BMI: 25.0–29.9
- Obese (Class I): 30.0–34.9
- Obese (Class II): 35.0–39.9
- Severely obese: 40.0+
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the healthy bmi threshold is lower — overweight begins at 23.0. Use our free BMI calculator above to find your personal BMI instantly, then cross-reference it against these NHS guidelines to understand where you fall.
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.
BMI Limitations and What Overweight Really Means
BMI limitations are important to understand. BMI doesn't distinguish between muscle and fat — an athlete with strong muscle mass may have a high BMI despite low body fat. It also ignores where fat is stored; excess weight around the waist carries greater health risk than weight distributed elsewhere. Waist circumference is often a better predictor of cardiovascular risk than BMI alone. The NHS recommends men keep waist circumference below 94cm and women below 80cm. Being overweight increases risk of type 2 diabetes, high blood pressure, and heart disease — but modest weight loss of just 5–10% can reduce these risks significantly. Your GP can assess your individual health picture beyond BMI.
- 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 overweight BMI threshold according to NHS guidelines?
According to NHS BMI range uk standards, overweight is a BMI of 25.0 to 29.9. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, overweight begins at BMI 23.0. Use our weight converter to check your weight in the right units, then use our free BMI calculator to find your exact BMI.
Is an overweight BMI necessarily unhealthy?
Not always. BMI is a screening tool with limitations — it doesn't account for muscle mass, fitness, or fat distribution. Someone with high muscle mass may have an overweight BMI but excellent health. However, being overweight does increase risk of type 2 diabetes, heart disease, and high blood pressure. Your GP can assess your individual health context beyond BMI alone.
How is overweight BMI calculated?
The BMI formula is: weight (kg) ÷ height (m)². For example, if you weigh 75kg and are 1.73m tall, your BMI is 75 ÷ (1.73 × 1.73) = 25.1, which falls in the overweight category. Our free BMI calculator on this page does this instantly.
What should I do if my BMI is overweight?
Speak to your GP, who can assess your individual health and advise on next steps. Even modest weight loss of 5–10% can improve blood pressure, blood sugar, and cholesterol. The NHS recommends sustainable loss of 0.5–1kg per week through balanced diet and physical activity. Track your progress using our free progress tracker.
Is waist circumference more important than overweight BMI?
Both matter. Waist circumference is often a better predictor of cardiovascular risk because it measures abdominal fat specifically, which is more harmful than fat elsewhere. The NHS recommends men keep waist under 94cm and women under 80cm. BMI gives overall context, but combined assessment is most useful for health planning.
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.