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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57.9 Kg In Stones And Pounds — What's Your BMI?
57.9 kg converts to 9 stone and 1.8 pounds in UK measurements. However, your BMI — a key health indicator — depends entirely on your height. At different heights, this same weight gives very different BMI results, ranging from underweight to overweight according to NHS guidelines. Use our free BMI calculator above to find your personal BMI, or read on to see what this weight means at common UK heights.
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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.
57.9 Kg BMI At Different Heights
To understand what 57.9kg means for your health, you need to calculate your BMI (Body Mass Index) — the formula is weight in kilograms divided by height in metres squared. Here's what 57.9kg gives you at typical UK heights:
- At 5ft 2in (157 cm): BMI of 23.5 — healthy weight (NHS category: 18.5–24.9)
- At 5ft 4in (163 cm): BMI of 21.8 — healthy weight
- At 5ft 6in (168 cm): BMI of 20.5 — healthy weight
- At 5ft 8in (173 cm): BMI of 19.3 — healthy weight
- At 5ft 10in (178 cm): BMI of 18.2 — healthy weight
- At 6ft (183 cm): BMI of 17.3 — underweight (NHS category: below 18.5)
You can convert kilograms to stone easily using our free weight converter tool, and calculate your exact BMI using the 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
NHS BMI categories for UK adults are: underweight (below 18.5), healthy weight (18.5–24.9), overweight (25.0–29.9), and obese (30.0+). However, BMI has important limitations — it doesn't distinguish between muscle and fat, so athletes may have a high BMI despite low body fat. It also doesn't account for where fat is stored; waist circumference matters too. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds due to higher health risks at the same weight. Your GP can provide personalised guidance on what your BMI 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.
What is 57.9 kg in stones and pounds?
57.9 kg converts to 9 stone and 1.8 pounds (or approximately 9st 2lbs). Use the standard kg to stone conversion: divide by 6.35. Our free weight converter above can do this instantly in any direction — kilos to stone, stone to kg, or stones and lbs.
Is 57.9 kg a healthy weight?
It depends on your height. At most UK heights between 5ft 2in and 5ft 10in, 57.9kg gives a healthy BMI according to NHS guidelines. Use our free BMI calculator on this page to find your exact BMI. If you're shorter than 5ft 2in, this weight may be overweight; if taller than 6ft, it may be underweight.
What BMI does 57.9 kg give at 5ft 6in?
At 5ft 6in (168 cm), 57.9 kg gives a BMI of 20.5, which falls squarely in the healthy weight range (18.5–24.9 according to NHS guidelines). This is considered a good health indicator for cardiovascular and metabolic health at that height.
Why does BMI change with height?
BMI accounts for both weight and height because the same weight distributed over a taller frame presents differently for health. A 57.9kg person at 5ft 2in has less height to distribute that weight, so BMI is higher than the same person at 5ft 10in. Height makes a major difference to what weight means healthwise.
Is BMI accurate for everyone?
BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat — athletes may have a high BMI with low body fat. It doesn't account for where fat is stored (waist circumference matters). For South Asian, Chinese, Black African, and Black Caribbean adults, NHS guidelines recommend lower BMI thresholds due to higher health risks. Your GP can give personalised advice about your weight and health.
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.