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 Does a BMI of 27 Mean in the UK?
A BMI of 27 places you in the overweight category according to NHS guidelines. This means your weight is above the healthy range for your height, which may increase your risk of certain health conditions. However, BMI is just one screening tool and doesn't account for muscle mass, fitness level, or where fat is stored on your body. Your GP can provide personalised advice about what your BMI means for your individual health. Use our free BMI calculator above to check your personal BMI and understand your health context better.
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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 What 27 Means
According to NHS guidance, a BMI of 27 falls firmly in the overweight category (BMI 25.0–29.9). The healthy BMI range for most UK adults is 18.5 to 24.9.
- BMI under 18.5: Underweight
- BMI 18.5–24.9: Healthy weight
- BMI 25.0–29.9: Overweight (where 27 sits)
- BMI 30.0–34.9: Obese (Class I)
- BMI 35.0 and above: Obese (Class II or III)
At a BMI of 27, you're in a position where modest lifestyle changes—such as increased physical activity and dietary adjustments—can have meaningful health benefits. The NHS recommends weight loss of 0.5 to 1 kg per week for sustainable results. Important note: BMI limitations mean this figure doesn't distinguish between muscle and fat, so athletes or very muscular individuals may have a BMI of 27 but still be healthy. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds due to higher cardiovascular risk at the same BMI level.
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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 Support and When to Seek Help
The NHS offers a structured weight management pathway with support at several levels. At a BMI of 27, your GP can discuss lifestyle interventions, refer you to community weight management programmes, or suggest digital tools to track progress. If you have weight-related health conditions—such as type 2 diabetes, high blood pressure, or sleep apnoea—your GP may recommend more intensive support or referral to specialist weight management services. Our free progress tracker and weight converter can help you monitor your journey and understand your weight in both metric and imperial measurements. Don't wait until BMI reaches 30 to take action—early intervention at the overweight stage often achieves the best long-term results.
- 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 27 considered obese?
No. A BMI of 27 is classified as overweight, not obese. The obese category begins at BMI 30.0 according to NHS guidelines. However, being in the overweight range does increase your risk of certain health conditions, and your GP may recommend lifestyle changes.
Should I lose weight if my BMI is 27?
This depends on your overall health, any weight-related conditions you may have, and your personal circumstances. Your GP can advise whether weight loss is appropriate for you. Even a 5–10% reduction in body weight can bring health benefits like improved blood pressure and better blood sugar control.
What's the difference between my BMI and body fat percentage?
BMI is calculated from height and weight only and doesn't distinguish between muscle and fat. Body fat percentage measures actual fat mass and is more precise. Someone with high muscle mass (like an athlete) may have a high BMI but low body fat. Your GP can discuss which measures are most relevant to your health.
How do I know my healthy weight range at a BMI of 27?
To find your healthy weight range, aim for a BMI between 18.5 and 24.9. The exact weight depends on your height. Use our free BMI calculator to find your personalised healthy weight range, or ask your GP for guidance tailored to your individual health profile.
Can I reduce my BMI without going to the gym?
Yes. Weight loss primarily comes from dietary changes creating a calorie deficit. The NHS recommends combining modest dietary changes with increased physical activity—which doesn't have to mean gym workouts. Walking, cycling, or everyday activities all count. Your GP or a weight management programme can suggest realistic approaches for you.
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.