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 Pounds — and What's Your BMI?
103kg converts to 16 stone 3 pounds in UK measurements. However, your BMI at this weight depends entirely on your height — the same weight can be a healthy BMI for a taller person or an overweight BMI for someone shorter. This guide shows you what BMI this weight gives at different heights, and where you fall on NHS categories. Use our free BMI calculator above to find your exact BMI instantly.
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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 — Examples by Height
At 103kg, your BMI varies significantly depending on your height. Here are typical examples:
- 160cm (5ft 3in): BMI 40.2 — Obese (Class III) according to NHS guidelines
- 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)
These examples show how the same weight in kilos to stone converts to very different health contexts. A healthy BMI is between 18.5 and 24.9 according to NHS guidelines. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply — healthy BMI starts at 18.5 and overweight begins at 23.0.
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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.
Understanding BMI Categories and Limitations
BMI is a useful screening tool, but it has important limitations. BMI does not distinguish between muscle and fat — an athlete may have a high BMI with low body fat, while someone sedentary may have a normal BMI with high body fat. Additionally, BMI does not account for where weight is carried on your body. Waist circumference is equally important: men should aim for under 94cm (37 inches), and women under 80cm (31.5 inches) for reduced health risk.
If you're concerned about your weight and health, your GP can provide personalised advice based on your individual circumstances, family history, and any existing health conditions. Convert your weight between metric and imperial using our free weight converter, and track progress over time with our progress tracker tool.
- 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 stones and pounds?
103kg equals 16 stone and 3 pounds exactly. To convert any kilograms to stone, divide by 6.35 (1 stone = 6.35kg). You can verify this instantly using the weight converter on this page, which handles stone and pounds conversions for any weight.
Is 103kg overweight for all heights?
Not necessarily. At 103kg, someone who is 185cm tall may fall into obese Class I, while someone 160cm tall would have a higher BMI in the severely obese range. Height dramatically affects BMI — taller individuals can weigh more while maintaining a lower BMI. Use our free BMI calculator to find your personal BMI.
What should I weigh to have a healthy BMI?
A healthy BMI of 18.5–24.9 requires different weights at different heights. At 170cm, a healthy weight is roughly 53–72kg. At 180cm, it's 60–81kg. Your GP or a healthcare professional can advise on a realistic target weight for your individual circumstances.
Why does the NHS mention different BMI categories for different ethnicities?
Research shows that people of South Asian, Chinese, Black African, and Black Caribbean heritage face higher health risks at lower BMI levels. The NHS therefore recommends lower thresholds for these groups — healthy BMI begins at 18.5 and overweight at 23.0, compared to 25.0 for other populations.
Is BMI the only measure of weight-related health?
No. Waist circumference, body fat percentage, physical fitness, blood pressure, and cholesterol levels are all important. BMI is a useful screening tool but doesn't account for muscle mass or fat distribution. Your GP can assess your overall health beyond BMI alone.
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.