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 45kg In Stone?
45kg is equivalent to 7 stone and 1.6 pounds (or approximately 7 stone 2lbs in rounded terms). This is a straightforward weight conversion using the standard UK measurement scale. For UK adults, understanding your weight in stone helps you compare against NHS health guidelines and check whether your weight falls within a healthy range. Use our free weight converter above to switch between kilograms, stone, and pounds instantly whenever you need it.
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.
45kg in UK Health Context
At 45kg, your weight depends heavily on your height to determine whether it falls within a healthy range according to NHS guidelines. For example, if you are 160cm (5ft 3in) tall, a weight of 45kg gives a BMI of 17.6, which sits comfortably in the healthy weight category (18.5–24.9). However, if you are taller — say 175cm (5ft 9in) — the same 45kg would result in a BMI of 14.7, which falls into the underweight category. This illustrates why BMI must be calculated using both weight and height. The NHS recommends a healthy BMI between 18.5 and 24.9 for most UK adults, though lower thresholds apply for adults of South Asian, Chinese, Black African, or Black Caribbean heritage. If you are concerned about being underweight or if your weight has changed suddenly, it is worth speaking to your GP for personalised health advice.
Our free BMI calculator above can instantly show you where your weight sits on the NHS health scale when you enter your height and weight.
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.
Weight Management and NHS Guidance
Whether 45kg is a healthy weight for you depends on your individual circumstances, including your height, age, muscle mass, and medical history. The NHS provides clear guidance: most UK adults should aim for a BMI between 18.5 and 24.9. You can check your personal healthy weight range using the BMI calculator on this page — it takes just seconds and gives you NHS-aligned context. If you have questions about your weight, whether you are concerned about being underweight, or if you want personalised advice on nutrition or health, your GP is the best starting point. They can assess your individual situation and refer you to additional support if needed, such as a dietitian or weight management service.
- 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 45kg a healthy weight?
It depends on your height. 45kg may be healthy for a shorter adult but underweight for someone taller. Use the BMI calculator on this page to check your personal BMI — enter your height and weight to see where you fall on the NHS healthy weight scale (18.5–24.9 is healthy for most adults).
How many pounds is 45kg?
45kg equals approximately 99.2 pounds (or 99 lbs). Using stone and pounds — the standard UK measurement — 45kg is 7 stone and 1.6 pounds. Use our free weight converter above to switch between metric and imperial units instantly.
What BMI is 45kg?
Your BMI at 45kg depends on your height. At 160cm you would have a BMI of 17.6 (healthy). At 175cm you would have a BMI of 14.7 (underweight). Always calculate BMI using both weight and height together — weight alone does not tell the full picture.
Should I be concerned if I weigh 45kg?
Only your GP can advise whether 45kg is healthy for you personally. If you have noticed sudden weight loss, feel unwell, or have other health concerns, speak to your GP. They can assess your individual health and provide personalised guidance.
How do I convert kg to stone accurately?
To convert kg to stone, divide the kilogram amount by 6.35029. So 45kg ÷ 6.35 = 7.09 stone. For quick conversions, use our free weight converter above — it handles all metric and imperial conversions instantly.
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.