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
13 Stone 11 Pounds in Kilograms
13 stone 11 pounds is equal to 87.54 kilograms. This conversion uses the standard UK measurement system where 1 stone equals 6.35029 kilograms. Whether you're tracking your weight for health reasons, comparing measurements, or using NHS guidelines, our free weight converter above makes it easy to switch between stone and pounds and kilograms instantly. Understanding your weight in both metric and imperial units helps you engage with health information from different sources.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 to Convert Stone and Pounds to Kilograms
To convert 13 stone 11 pounds to kilograms, use this simple formula:
- Multiply stone by 6.35029
- Multiply pounds by 0.453592
- Add both results together
For 13st 11lbs: (13 × 6.35029) + (11 × 0.453592) = 82.554 + 4.989 = 87.54 kg
This kilogram to stone conversion works for any weight. The weight converter tool on this page calculates it instantly, or you can use the same formula for any stone and pounds measurement. Many UK adults find it helpful to track weight in both units, especially when reading NHS health guidance which often uses kilograms.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Weight Context at 13 Stone 11 Pounds
At 13st 11lbs (87.54 kg), your health context depends entirely on your height. For example, at an average UK male height of 5ft 9in (175 cm), this weight gives a BMI of approximately 30.6, which falls into the obese category. At 5ft 6in (168 cm), the BMI would be around 32.1. Our free BMI calculator above shows your exact BMI instantly when you enter your height and weight. A BMI above 30 may indicate increased health risks, but your GP can provide personalised guidance based on your individual circumstances, fitness level, and medical history.
- 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 is 13 stone 11 in kilograms exactly?
13 stone 11 pounds equals 87.54 kilograms. The calculation is: (13 × 6.35029) + (11 × 0.453592) = 87.54 kg. This is the standard conversion used across UK health services and NHS guidance.
How do I convert any stone and pounds to kilograms?
Multiply the stone value by 6.35029 and the pounds value by 0.453592, then add them together. For example, 10 stone 7 pounds = (10 × 6.35029) + (7 × 0.453592) = 66.68 kg. Use our weight converter tool above for instant calculations.
Is 87.54 kg a healthy weight?
Whether 87.54 kg is healthy depends on your height and overall health. Use our free BMI calculator to find your BMI instantly — at different heights, this weight produces different health categories. Your GP can advise whether this weight is appropriate for you personally.
How does 13 stone 11 compare to average UK weight?
The average UK adult male weighs around 85.7 kg (13st 7lbs), so 87.54 kg is slightly above average. However, average weight does not equal healthy weight — BMI and other health factors matter more. Use our calculator tools to assess your personal health context.
Can I lose weight safely from 13 stone 11 pounds?
Yes. The NHS recommends losing weight at a rate of 0.5–1 kg per week through a combination of reduced-calorie diet and increased physical activity. Our free progress tracker helps you monitor weight loss over time. Always speak to your GP before making significant dietary changes.
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.