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 11 in Kilograms?
13 stone 11 pounds (13st 11) converts to approximately 87.55 kilograms. This conversion uses the standard UK to metric formula. If you're tracking your weight, understanding your weight in both UK measurements (stone and pounds) and metric kilograms is useful for NHS health guidance, fitness tracking, and international health contexts. Our free weight converter above can help you switch between these measurements instantly, and the BMI calculator on this page shows how your weight relates to your health status.
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 13st 11 to Kilograms
To convert 13 stone 11 pounds to kilograms, use the standard conversion formula: multiply the stone by 6.35029, then multiply the pounds by 0.453592, and add them together.
- 13 stone: 13 × 6.35029 = 82.55 kg
- 11 pounds: 11 × 0.453592 = 4.99 kg
- Total: 82.55 + 4.99 = 87.54 kg (approximately 87.55 kg)
For quick conversions, use our free weight converter on this page — it calculates this automatically. You can also use the reverse formula to convert kilograms back to stone and pounds, which is helpful when reading NHS health guidance or international fitness resources that use metric measurements.
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.
BMI Context for 13st 11
At 13st 11 (87.55 kg), your BMI depends on your height. For example, at 5ft 9 inches (175 cm), a weight of 13st 11 gives a BMI of approximately 29.2, which falls in the overweight category (25.0–29.9) according to NHS guidelines. However, BMI is a screening tool only and does not account for muscle mass or where fat is stored. Use our free BMI calculator above to find your personal BMI and explore healthy weight ranges for your height. Your GP can provide tailored advice about what a healthy weight means for your individual health.
- 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.
Is 13st 11 a healthy weight?
Whether 13st 11 is healthy depends on your height, age, and overall health. Use the BMI calculator on this page to find your BMI. For most adults, a healthy BMI is 18.5–24.9 according to NHS guidelines. At 13st 11, you may be in the overweight or obese range depending on your height. Your GP can give you personalised advice.
How much is 13st 11 in kilograms exactly?
13st 11 converts to 87.55 kilograms (or 87.54 kg using precise calculation). One stone equals 6.35029 kg, and one pound equals 0.453592 kg. Our weight converter above calculates this instantly if you need to switch between different units.
What is the healthy weight range for someone at 13st 11?
Healthy weight depends on your height. At 5ft 9 inches, a healthy weight is approximately 8st 5lbs to 11st 3lbs (53–71 kg). At 6ft tall, it's approximately 9st 3lbs to 12st 3lbs (59–78 kg). Use the BMI calculator on this page to find your specific healthy weight range based on your exact height.
Can weight loss medications help if I'm 13st 11?
Weight loss medications like Mounjaro or Wegovy are prescription-only and require a clinical assessment from a qualified prescriber or GP. Eligibility typically depends on your BMI, health conditions, and individual circumstances. Our GLP-1 weight loss calculator can help you explore potential outcomes if appropriate for you — always discuss options with your GP first.
How do I convert kilograms back to stone and pounds?
To convert kg to stone, divide by 6.35029. To convert kg to pounds, multiply by 2.20462. For example, 87.55 kg ÷ 6.35029 = 13.79 stone (approximately 13st 11). Use our free weight converter on this page for instant conversions in both directions.
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.