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 is 13 Stone 12 Pounds in Kilograms?
13 stone and 12 pounds equals approximately 88 kilograms. Your BMI depends on your height, so the same weight gives very different health contexts depending on how tall you are. Below, we show what BMI this weight produces at six common UK heights, and where each falls within NHS weight categories. Use our free BMI calculator above to find your exact BMI instantly.
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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.
BMI at Different Heights for 88 kg
At 13 stone 12 pounds (88 kg), your BMI varies significantly based on height. Here's how this weight converts across common heights:
- 5ft 4in (163 cm): BMI = 33.0 (Obese Class I)
- 5ft 6in (168 cm): BMI = 31.2 (Obese Class I)
- 5ft 8in (173 cm): BMI = 29.4 (Overweight)
- 5ft 10in (178 cm): BMI = 27.8 (Overweight)
- 6ft 0in (183 cm): BMI = 26.3 (Overweight)
- 6ft 2in (188 cm): BMI = 24.9 (Healthy weight)
These categories follow NHS guidelines. The same weight can represent healthy, overweight, or obese categories depending entirely on height. For a precise personal assessment, calculate your own BMI using the weight converter and 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.
Understanding BMI Categories and Limitations
The NHS BMI categories provide a useful screening tool, but they have important limitations. BMI does not distinguish between muscle and fat — athletes may have a high BMI with low body fat. It also ignores where fat is stored (waist measurement matters for cardiovascular health), and may be less accurate for very muscular individuals or older adults with age-related muscle loss.
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 the same BMI. If you're concerned about your weight or health, your GP can provide personalised guidance beyond 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.
How do I convert 13 stone 12 pounds to kilograms exactly?
13 stone 12 pounds = (13 × 6.35029) + (12 × 0.453592) = 88.0 kg. Use the kilogram to stone conversion formula: multiply stones by 6.35029, then add pounds multiplied by 0.453592. Our free weight converter above makes this instant.
Is 88 kg a healthy weight for an adult?
It depends on your height. At 88 kg, you could be anywhere from healthy weight to obese Class I, depending on how tall you are. Use our BMI calculator to find your personal category. If you're concerned, your GP can assess your individual health context.
What does "Obese Class I" mean in NHS terms?
NHS Obese Class I refers to a BMI of 30.0–34.9. It indicates increased health risks including type 2 diabetes and cardiovascular disease. However, BMI is just one screening tool. Waist measurement, fitness level, and family history also matter. Discuss with your GP about personalised health advice.
How do I find my healthy weight range for my height?
Healthy BMI ranges from 18.5 to 24.9 according to NHS guidelines. Use this to calculate healthy weight: multiply 18.5 by your height in metres squared for the lower bound, and 24.9 by the same for the upper bound. Our BMI calculator shows this instantly.
Can I lose weight safely and sustainably at home?
Yes. The NHS recommends losing 0.5–1 kg per week through a calorie deficit combined with increased physical activity. Sustainable approaches include Mediterranean diet patterns and behaviour change. For structured support, NHS services offer free weight management programmes. Track your progress with our free progress tracker.
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.