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 58.9kg in stone and what does your BMI mean?
58.9kg is equivalent to 9 stone 4.3 pounds. However, your BMI at this weight depends entirely on your height — the same weight gives a very different BMI result for a 5ft 2in person compared to a 6ft person. Use our free BMI calculator above to check your personal BMI instantly, or read on to see example BMI values at different heights and what the NHS considers a healthy range.
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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 58.9kg for different heights
Since BMI combines weight and height, 58.9kg produces different results depending on how tall you are. Here's what your BMI would be at common UK heights:
- 5ft 0in (152cm): BMI of 25.6 — overweight category
- 5ft 4in (163cm): BMI of 22.2 — healthy weight
- 5ft 8in (173cm): BMI of 19.7 — healthy weight
- 5ft 10in (178cm): BMI of 18.6 — healthy weight
- 6ft 0in (183cm): BMI of 17.6 — underweight category
At 58.9kg, you can see how height makes a significant difference. Someone 5ft 0in at this weight would be considered overweight by NHS standards, whilst someone 5ft 8in would be in the healthy range. Use the weight converter and BMI calculator on this page to check your own height and exact BMI.
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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 NHS BMI categories and limitations
The NHS defines a healthy BMI as 18.5 to 24.9 for most UK adults. At 58.9kg, you're within the healthy range if you're taller than approximately 5ft 2in. However, BMI has important limitations — it doesn't distinguish between muscle and fat, so athletes or very muscular individuals may have a higher BMI despite being fit. BMI also doesn't account for where fat is stored, which matters for health. Your GP can provide personalised advice about whether your weight is healthy for your individual circumstances, medical history, and ethnicity. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends assessing health risk at slightly lower BMI thresholds.
- 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 58.9kg in stone and pounds?
58.9kg converts to 9 stone 4.3 pounds. To convert kilograms to stone, divide by 6.35029. This is a straightforward conversion between metric (kg) and imperial (stone) measurements commonly used in the UK for tracking body weight.
Is 58.9kg a healthy weight?
It depends on your height. At 58.9kg, a BMI of 18.5–24.9 (healthy range) is achieved if you're roughly 5ft 2in or taller. Shorter individuals at this weight may fall into the overweight category, whilst taller individuals may be underweight. Use our free BMI calculator to check your personal result.
What does BMI measure exactly?
BMI (body mass index) is a simple measure calculated from weight and height to screen for potential health risks related to excess weight. It's expressed as kg/m² and is widely used in NHS health assessments, though it has limitations — it doesn't distinguish between muscle and fat or account for fat distribution.
Why does height matter so much for BMI?
BMI divides weight by height squared, so taller individuals have proportionally lower BMI at the same weight. A 5ft person and a 6ft person at 58.9kg have very different BMI results because the formula accounts for how weight is distributed across different body frames.
Should I use BMI alone to assess my health?
No — NHS guidance recommends using BMI alongside other measures like waist circumference and your overall health history. Waist measurement, fitness level, medical conditions, and family history all contribute to your true health picture. Your GP can give you personalised advice beyond just your BMI number.
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.