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 123kg in stone and pounds?
123 kilograms is equal to 19 stone and 5.5 pounds (or 19st 5.5lbs). This is a straightforward kilogram to stone conversion using the standard UK measurement system. If you need to convert kilograms to stone regularly, understanding the formula makes it simple: divide the kilogram amount by 6.35029 to get stone, or multiply by 2.20462 for pounds. At this weight, BMI context varies significantly depending on your height, so it's worth checking where you sit on the NHS healthy weight scale. Use our free weight converter above to switch between metric and imperial measurements 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.
Conversion table: 123kg and nearby values
To convert 123kg to stone, divide 123 by 6.35029, which gives you 19.38 stone (or 19 stone 5.5 pounds). Here's a quick reference table showing 123kg alongside nearby kilogram values, all converted to both stone and pounds:
- 118kg = 18st 8.5lbs (260.1 lbs)
- 120kg = 18st 12.7lbs (264.6 lbs)
- 122kg = 19st 3.3lbs (268.8 lbs)
- 123kg = 19st 5.5lbs (271.2 lbs)
- 124kg = 19st 7.7lbs (273.4 lbs)
- 125kg = 19st 9.9lbs (275.6 lbs)
- 128kg = 20st 2.5lbs (282.2 lbs)
The kilogram to stone conversion formula is straightforward: weight in kg ÷ 6.35029 = weight in stone.
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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.
BMI and healthy weight context at 123kg
At 123kg, your BMI depends on your height. For example, if you're 5ft 8in (173cm), a weight of 123kg gives a BMI of approximately 41, which falls in the severely obese range according to NHS guidelines. At 5ft 10in (178cm), the same weight gives a BMI of around 38, still in the obese category. A healthy weight range at 5ft 8in would be 55–74kg (8st 10lbs to 11st 10lbs). Use our free BMI calculator above to find your personal BMI instantly, and remember that BMI is a screening tool — it doesn't account for muscle mass or where fat is stored, so your GP can provide personalised health advice.
- 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 123kg to stone manually?
Divide 123 by 6.35029 to get stone. 123 ÷ 6.35029 = 19.38 stone. To express this as stone and pounds, multiply the decimal (0.38) by 14 to get pounds: 0.38 × 14 = 5.5 pounds. So 123kg = 19 stone 5.5 pounds.
What is 123kg in just pounds?
Multiply 123kg by 2.20462 to convert to pounds. 123 × 2.20462 = 271.2 pounds. This is useful for comparing UK weights to imperial-only systems, though UK adults typically express weight in stone and pounds rather than total pounds.
Is 123kg a healthy weight?
Whether 123kg is healthy depends on your height, age, and overall health. Use our free BMI calculator to check your personal BMI. Generally, the NHS recommends a BMI between 18.5 and 24.9 for adults, though individual health needs vary. Your GP can advise on what's healthy for you.
What's the formula to convert kilograms to stone?
The formula is: weight in kg ÷ 6.35029 = weight in stone. Alternatively, to convert kg to pounds, multiply by 2.20462. These standard conversion factors work for any kilogram value you want to convert to UK measurements.
How does 123kg compare to average UK adult weight?
The average UK adult man weighs around 85.7kg (13st 7lbs) and the average woman weighs around 71.6kg (11st 3lbs). At 123kg, this weight is significantly above average for both sexes. Weight is affected by many factors including genetics, medical conditions, and lifestyle. Our progress tracker can help you monitor changes over time if you're managing your weight.
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.