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
Is 7.9 Kg In Stone A Healthy Weight?
7.9 kg converts to 1 stone 3 lbs in UK measurements. Whether this is a healthy weight depends entirely on your height. For a child or young person this may be appropriate, but for an adult this would be significantly underweight according to NHS guidelines. Use our free BMI calculator above to check your personal healthy weight range based on your height, or read on to understand how NHS weight categories work and what the healthy weight range is for different 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.
Healthy Weight Ranges By Height
To determine if 7.9kg (1 stone 3 lbs) is healthy, you need to know your height and calculate your BMI. The NHS defines a healthy weight range as a BMI between 18.5 and 24.9 for most UK adults. Here's how different heights affect whether 7.9kg would be healthy:
- At 100 cm (3ft 3in): 7.9kg gives a BMI of 7.9 — significantly underweight
- At 110 cm (3ft 7in): 7.9kg gives a BMI of 6.5 — significantly underweight
- At 120 cm (3ft 11in): 7.9kg gives a BMI of 5.5 — significantly underweight
At standard adult heights, 7.9kg would be far below the healthy weight range. For reference, at 160 cm (5ft 3in), the healthy weight range is approximately 47–63 kg. To convert kilograms to stone accurately and check your own healthy weight, use the weight converter on this page alongside your height measurements.
Clinically BackedWeight Loss
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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.
NHS Weight Guidance And Next Steps
If your current weight is significantly below the healthy range for your height and age, it's important to speak with your GP. Being underweight can affect bone health, immune function, and energy levels. The NHS recommends a BMI of 18.5–24.9 for healthy adults, though for people of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply.
Beyond BMI, waist circumference also matters: men should aim for under 94 cm (37 inches), and women under 80 cm (31.5 inches) for healthy metabolic risk. If you're uncertain about your weight category, your GP can provide personalised guidance based on your individual health, age, and circumstances.
- 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 7.9 kg in stone and pounds?
7.9 kg converts to 1 stone and 3 pounds (1st 3lbs). To convert kilograms to stone using the standard stone to kg conversion formula, divide 7.9 by 6.35 to get the stone equivalent. You can also use our free weight converter above for instant conversions between metric and imperial units.
Is 7.9 kg a healthy weight for an adult?
For most UK adults, 7.9 kg is significantly underweight. The healthy weight range depends on height — at average adult heights (160–180 cm), healthy weights are typically 50–85 kg. A GP can assess whether your weight is healthy for your individual age, height, and health circumstances.
How do I know if my weight is healthy?
Calculate your BMI using your weight in kilograms and height in metres. The NHS considers a BMI of 18.5–24.9 healthy for most adults. You can use our free BMI calculator on this page to check your personal BMI instantly, or speak with your GP for personalised advice.
What if my weight is significantly below the healthy range?
Being underweight can affect health. Speak with your GP if your weight is consistently below the healthy range for your height. They can investigate possible causes and recommend nutritional or medical support if needed. Your GP may refer you to a dietitian for personalised dietary advice.
Does waist measurement matter as well as weight?
Yes. Waist circumference is an important health indicator alongside weight and BMI. NHS guidelines recommend men keep waist circumference under 94 cm (37 inches) and women under 80 cm (31.5 inches) for metabolic health. Your GP can measure and assess your waist as part of a full health check.
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.