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
Are You Overweight? Check Your BMI Now
Wondering am I overweight? The NHS defines overweight as a BMI between 25 and 29.9 for most adults. Finding out whether you fall into this category is straightforward — you can use your height and weight to calculate your BMI instantly. Understanding where you sit on the overweight health spectrum helps you make informed decisions about your health. This guide explains NHS categories, what overweight means for your wellbeing, and what steps you can take next, with practical support tailored for UK women.
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.
Understanding Overweight — NHS BMI Categories
The NHS overweight threshold starts at a BMI of 25.0. Here's how the categories break down according to NHS guidelines:
- Healthy weight: BMI 18.5–24.9
- Overweight: BMI 25.0–29.9
- Obese (Class I): BMI 30.0–34.9
- Obese (Class II): BMI 35.0–39.9
- Severely obese (Class III): BMI 40.0 and above
If you have a BMI in the 25–29.9 range, you are classified as overweight. However, BMI does not account for muscle mass, so athletes or very active women may have a higher BMI but lower body fat. Use our free BMI calculator above to find your personal BMI instantly — it takes just seconds and gives you a clear picture of where you stand. Your healthy weight range depends on your height; the calculator shows this automatically.
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.
Next Steps — Waist Measurement and What to Do
Alongside BMI, the NHS recommends checking your waist circumference as a complementary health check. For women, a waist measurement over 80cm (31.5 inches) suggests increased health risk, and over 88cm (34.5 inches) indicates high risk. Carrying excess weight around the middle is particularly linked to type 2 diabetes and heart disease risk. If you're overweight by BMI, or concerned about your weight check result, your next step is simple: speak to your GP, who can discuss your individual health and recommend support. Options may include lifestyle changes, behaviour change programmes, or — if clinically appropriate — prescription weight management treatments. Track your progress using our free progress tracker, and remember that even a 5–clinically studied weight loss can bring meaningful health benefits.
- 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 BMI means I'm overweight?
According to NHS guidelines, a BMI of 25.0 to 29.9 is classified as overweight. Use our BMI calculator above to find your personal BMI by entering your height and weight — it takes seconds and tells you exactly where you sit on the NHS scale.
Is being overweight dangerous?
Carrying excess weight increases your risk of type 2 diabetes, heart disease, high blood pressure, and certain cancers. However, losing even 5–10% of your body weight can reduce these risks significantly. Your GP can discuss your individual health picture and support options.
How do I calculate if I'm overweight?
BMI is calculated by dividing your weight in kg by your height in metres squared. Our free BMI calculator on this page does this automatically — just enter your height and weight in UK measurements (stone, pounds, or kg) and you'll get your result instantly.
What's the difference between overweight and obese?
Overweight is a BMI of 25.0–29.9; obese starts at BMI 30.0. These are medical classifications based on health risk. Both are associated with increased health risks, but obesity carries greater risk. Your GP can advise you on what's relevant to your individual health.
What should I do if I'm overweight?
Start by speaking to your GP about your health and weight. Options include NHS lifestyle programmes, behaviour change support, increased physical activity, and dietary changes. If appropriate, your GP may refer you to specialist weight management services or discuss prescription options. Use our progress tracker to monitor your journey.
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.