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 Good BMI Range? NHS Guidelines Explained
A good BMI range according to NHS guidance is between 18.5 and 24.9 for most UK adults. This is classed as a "healthy weight" and suggests lower health risks associated with excess weight. However, BMI is just one screening tool — it doesn't account for muscle mass, where fat is stored, or individual health circumstances. Your GP can provide personalised advice about what a healthy BMI means for you specifically. Use our free BMI calculator above to check where you fall within the healthy BMI range.
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 Categories and Healthy Weight Thresholds
The NHS defines a good BMI range as 18.5 to 24.9 for the general adult population. This category is associated with the lowest health risks from excess weight. The full NHS BMI categories are:
- Below 18.5: Underweight — may indicate insufficient body weight
- 18.5–24.9: Healthy weight — the good BMI range with lower health risks
- 25.0–29.9: Overweight — increased health risk compared to healthy weight
- 30.0–34.9: Obese (Class I) — significantly increased health risks
- 35.0–39.9: Obese (Class II) — higher health risks
- 40.0+: Severely obese (Class III) — substantial health risks
It's important to note that the good BMI range uses the BMI formula: weight (kg) ÷ height (m)². For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds, with a healthy BMI starting at 18.5 and extending to 22.9 — because these groups face higher health risks at standard BMI levels.
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.
NHS Weight Management and When to Seek Support
If your BMI falls outside the good BMI range, the NHS offers support through its weight management pathway. Tier 1 includes self-help tools and digital programmes; Tier 2 provides GP-led behaviour change support; and Tier 3 offers specialist multidisciplinary weight management services where prescription medications may be considered. You can discuss your BMI and weight health with your GP at any time. Remember that BMI limitations exist — it doesn't distinguish between muscle and fat, so athletes or very muscular individuals may have a higher BMI without excess body fat. Waist circumference and overall health context matter too. The BMI calculator on this page helps you find your personal BMI instantly alongside NHS health context.
- 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.
Is a BMI of 24 considered a good BMI range?
Yes. A BMI of 24 falls comfortably within the NHS-defined healthy weight range of 18.5–24.9. This is associated with lower health risks and is generally considered a good BMI for most UK adults. However, individual health depends on many factors beyond BMI alone — your GP can give you personalised guidance.
What BMI is considered overweight according to NHS guidance?
According to NHS standards, a BMI of 25.0–29.9 is classified as overweight. This range indicates increased health risk compared to the healthy BMI range (18.5–24.9). If your BMI falls in this range, lifestyle changes or GP support may be beneficial.
Why is the good BMI range different for people of South Asian heritage?
The NHS recommends a lower healthy BMI range (18.5–22.9) for South Asian, Chinese, Black African, and Black Caribbean adults because research shows these populations face higher risks of type 2 diabetes and heart disease at standard BMI levels. This reflects different health risk profiles at the same BMI.
Can I be healthy with a BMI outside the good BMI range?
BMI is a useful screening tool but has limitations. It doesn't account for muscle mass, bone density, age, or where fat is stored. Some athletic individuals may have a higher BMI but excellent health. Your GP can assess your overall health picture beyond BMI alone using waist measurement, blood pressure, and other markers.
How do I calculate my personal BMI to see if it's in the good range?
Use the BMI calculator on this page — it instantly shows your BMI and which NHS category you fall into. Alternatively, divide your weight in kg by your height in metres squared. For example, if you weigh 70kg and are 1.73m tall: 70 ÷ (1.73)² = 23.4 BMI, which is in the healthy good BMI range.
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.