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
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What is 103kg in stones and what's the BMI?
At 103kg, your weight converts to 16 stone 3 pounds (or 227 lbs). However, your BMI depends entirely on your height — the same weight can be healthy, overweight, or obese depending on how tall you are. Use our free BMI calculator above to find your exact BMI, then check where it falls on the NHS weight categories. This guide shows you what 103kg means for different heights across the UK.
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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.
BMI at 103kg for different heights
Your BMI at 103kg varies significantly by height. Here are examples showing kilos in stone alongside BMI at common adult heights:
- 160cm (5ft 3in): BMI 40.2 — Severely obese (Class III)
- 165cm (5ft 5in): BMI 37.8 — Obese (Class II)
- 170cm (5ft 7in): BMI 35.6 — Obese (Class II)
- 175cm (5ft 9in): BMI 33.6 — Obese (Class I)
- 180cm (5ft 11in): BMI 31.7 — Obese (Class I)
- 185cm (6ft 1in): BMI 30.1 — Obese (Class I)
At every height shown, 103kg falls into the obese category according to NHS guidelines. To get your personal BMI and see what weight range would be healthy for your specific height, calculate your BMI now using the 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.
NHS BMI categories and what they mean
The NHS BMI categories help determine health risk. A healthy BMI is between 18.5 and 24.9, and at 103kg, you would need to be very tall (around 210cm/6ft 10in) to fall into this range — which is well above average adult height.
Important limitations: BMI does not account for muscle mass, so very muscular individuals may have a higher BMI without excess fat. Additionally, for adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds because these groups face higher health risks at lower weights. Your GP can provide personalised advice about what your weight means for your individual health. Use the weight converter on this page to switch between metric and imperial measurements at any time.
- 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.
How do I convert 103kg to stone and pounds?
Divide 103kg by 6.35 to get stone: 103 ÷ 6.35 = 16.2 stone. This equals 16 stone 3 pounds (multiply the 0.2 by 14 to get pounds). You can also use our free weight converter above for instant metric to imperial weight conversions.
What BMI should I aim for?
The NHS recommends a healthy BMI of 18.5 to 24.9 for most adults. At 103kg, reaching this range would require losing significant weight. Your GP can advise on realistic and safe weight loss targets for your height and health circumstances. Even losing 5% of body weight can improve health outcomes.
Is 103kg overweight at my height?
At 103kg, BMI falls into the obese category at all common UK adult heights. Use our BMI calculator above to check your specific BMI by entering your height. This will show you exactly which NHS category you fall into and what healthy weight ranges would be for you personally.
Can I lose weight safely from 103kg?
The NHS recommends losing 0.5 to 1kg per week through a calorie deficit combined with increased physical activity. This is sustainable and reduces muscle loss. Faster weight loss may be possible with medical support. Always consult your GP before starting any significant weight loss programme or considering prescription weight loss medication.
How much weight do I need to lose to reach a healthy BMI?
The amount varies by your height. For example, at 175cm (5ft 9in), a healthy BMI requires a weight of roughly 55–76kg. Use our free BMI calculator to enter your height and see the healthy weight range for you, then track your progress with our progress tracker as you work towards it.
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.