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
A BMI of 34 — What This Means
A BMI of 34 falls into the obese (Class I) category according to NHS guidelines. This means your weight is significantly above the healthy range for your height, which may increase your risk of serious health conditions like type 2 diabetes, heart disease, and high blood pressure. The good news is that even modest weight loss can improve your health. Understanding your BMI is the first step — use our free BMI calculator above to confirm your personal BMI and explore what support options might be available to you through your GP.
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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 BMI of 34 Compares to NHS Categories
The NHS BMI formula divides your weight in kilograms by your height in metres squared. A BMI of 34 falls solidly in the obese (Class I) range, which spans from 30.0 to 34.9 on the NHS bmi categories uk scale. The healthy BMI range is 18.5 to 24.9, meaning you would need to lose roughly 5–10 kg (depending on your height) to reach the overweight threshold of 29.9. For example, someone who is 1.70m tall with a BMI of 34 weighs approximately 98 kg (15 stone 4 lbs) — moving to a BMI of 29.9 would require losing about 7 kg. More severe obesity (Class II) begins at 35.0, and Class III (severely obese) at 40.0. If you're uncertain about your exact BMI, calculate it now using the bmi calculator on this page.
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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.
BMI Limitations and What Else Matters
While BMI is a useful screening tool, it has important bmi limitations — it doesn't distinguish between muscle and fat, so an athlete with high muscle mass may have a high BMI despite low body fat. BMI doesn't account for where fat is stored, and waist circumference is equally important: men should aim for under 94 cm (37 inches), and women under 80 cm (31.5 inches). Age, ethnicity, and bone density also affect health risk. For a comprehensive health picture, your GP may also check blood pressure, blood sugar levels, and cholesterol. These factors together give a much clearer view of your overall health status than BMI alone.
- 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 health risks are associated with a BMI of 34?
A BMI of 34 increases your risk of type 2 diabetes, heart disease, high blood pressure, stroke, certain cancers, and sleep apnoea. These risks rise significantly at this BMI level compared to healthy weight. Even losing 5–10% of your body weight can meaningfully reduce these risks and improve blood sugar control, blood pressure, and cholesterol levels.
How much weight would I need to lose to leave the obese category?
You'd need to reach a BMI below 30.0 to move into the overweight category. The exact weight loss depends on your height. For a 1.70m tall person at BMI 34, that's roughly 7–8 kg (1 stone). Your GP can help you set a realistic, sustainable target and discuss support options including lifestyle changes or prescription weight loss treatment.
Is a BMI of 34 considered seriously obese?
A BMI of 34 is classified as obese (Class I), not severely obese. Class I obesity spans 30.0–34.9. Severely obese (Class III) starts at 40.0. That said, a BMI of 34 does increase health risks significantly, and your GP may recommend action to prevent weight-related complications. The NHS Weight Management pathway can help.
Can I improve my health with a BMI of 34 without losing weight?
Weight loss is the most effective strategy, but you can improve some health markers through increased physical activity and a healthier diet even before significant weight loss occurs. However, to meaningfully reduce disease risk associated with a BMI of 34, weight loss of 5–10% is typically recommended by NHS guidelines alongside lifestyle changes.
What support is available on the NHS for a BMI of 34?
Your GP can refer you to a tier 2 or tier 3 NHS weight management service, which offers behaviour change programmes, dietary support, and potentially prescription weight loss treatment. Eligibility for medications like Mounjaro or Wegovy varies by region and individual circumstances. Private options are also available following an online clinical assessment with a UK-licensed prescriber.
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.