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 45 Kg In Stone And Pounds?
45 kilograms is equivalent to 7 stone and 1.6 pounds in UK measurements. If you're converting your weight to stone, or checking whether 45 kg falls into a healthy weight range, the answer depends on your height. Use our free weight converter to switch instantly between kg, stone, and lbs. Your BMI at this weight will vary based on your height, and the NHS BMI calculator can help you determine whether this weight is healthy for you personally.
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.
45 Kg BMI At Different Heights
At 45 kg, your BMI depends entirely on your height. Here's what 45 kg means across common UK heights:
- 150 cm (4ft 11in): BMI of 20 — healthy weight (NHS category)
- 160 cm (5ft 3in): BMI of 17.6 — healthy weight
- 165 cm (5ft 5in): BMI of 16.5 — healthy weight (lower end)
- 170 cm (5ft 7in): BMI of 15.5 — underweight
- 175 cm (5ft 9in): BMI of 14.7 — underweight
- 180 cm (5ft 11in): BMI of 13.9 — underweight
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends slightly different thresholds. Use our free BMI calculator above to check your exact BMI and health category instantly.
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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.
NHS BMI Categories And Weight Health
The NHS defines healthy weight as a BMI between 18.5 and 24.9 for most adults. At 45 kg, if you're under 165 cm (5ft 5in) tall, you're likely in the healthy range. If you're taller than this, 45 kg may fall into the underweight category, which can increase risk of bone density loss and other health concerns. BMI is a useful screening tool but has important limitations — it doesn't distinguish between muscle and fat, or account for where weight is stored. Your GP can give you personalised advice about whether 45 kg is healthy for your individual 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.
Is 45 kg a healthy weight?
It depends on your height. At 45 kg, if you're around 150–165 cm tall, you're likely in the healthy BMI range. If you're taller, this weight may be underweight. Use our free BMI calculator above to check your exact category and discuss any concerns with your GP.
How do I convert 45 kg to stone and pounds?
45 kg equals 7 stone and 1.6 pounds. To convert kilograms to stone, divide by 6.35. You can also use our free weight converter on this page to switch between kg, stone, and lbs instantly.
What does underweight mean for health?
A BMI below 18.5 is classified as underweight. This can increase risk of weak bones, nutritional deficiency, and weakened immunity. If your BMI is underweight, speak to your GP about nutrition and whether weight gain is appropriate for your health.
Can BMI be inaccurate?
Yes. BMI doesn't account for muscle mass, bone density, or fat distribution. Athletes may have high BMI but low body fat. Your GP can assess your health using BMI alongside other measurements like waist circumference and blood pressure.
Should I be concerned if I weigh 45 kg?
Not necessarily — 45 kg is healthy for some people and underweight for others, depending entirely on height, age, muscle mass, and individual health factors. Your GP can give personalised advice based on your complete health picture.
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.