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
1.55 Kg To Lbs — What's Your BMI At This Weight?
1.55 kg converts to approximately 3.42 pounds. However, whether this weight is healthy for you depends entirely on your height. BMI is calculated using both weight and height together, so the same weight can fall into different NHS health categories depending on how tall you are. Use our free BMI calculator above to check your personal BMI instantly, and see where you stand according to NHS guidelines.
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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.
What BMI Does 1.55 Kg Give At Different Heights?
At 1.55 kg, your BMI varies significantly depending on your height. Here are examples using the standard BMI formula:
- At 150 cm (4ft 11in): BMI 6.9 — underweight (below 18.5)
- At 160 cm (5ft 3in): BMI 6.1 — underweight
- At 170 cm (5ft 7in): BMI 5.4 — underweight
- At 175 cm (5ft 9in): BMI 5.0 — underweight
- At 180 cm (5ft 11in): BMI 4.8 — underweight
- At 190 cm (6ft 3in): BMI 4.3 — underweight
At this very low weight, all heights fall into the underweight category. If you're concerned about your weight or health, speak to your GP for personalised advice. Try the weight converter on this page to see 1.55kg in stones and pounds.
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.
Understanding NHS BMI Categories And Limitations
The NHS BMI categories 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 high BMI despite low body fat. BMI also doesn't account for where fat is stored; waist circumference matters for health risk. For South Asian, Chinese, Black African, or Black Caribbean adults, the NHS recommends lower BMI thresholds due to higher health risks at the same BMI. Use our free BMI calculator above for your personal assessment, then discuss results with your GP if you have health concerns.
- 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 1.55 kg a healthy weight for an adult?
1.55 kg is an extremely low weight for any adult and falls into the underweight category at all heights. This weight would suggest either a measurement error or a serious health concern. Please contact your GP immediately if you or someone you know weighs this little.
How do I convert 1.55 kg to stone?
To convert kilograms to stone, divide by 6.35. So 1.55 kg ÷ 6.35 = 0.24 stone (approximately). Our free weight converter above instantly shows 1.55kg in stone, pounds, and kilograms for easy reference.
What's the difference between kg and lbs?
Kilograms (kg) are metric units used by the NHS and most health services in the UK. Pounds (lbs) are imperial units. One kilogram equals 2.20462 pounds. UK adults often use stone and pounds for body weight, even though medical professionals typically work in kilograms.
Can BMI be inaccurate?
Yes, BMI has limitations. It doesn't distinguish muscle from fat, doesn't account for fat distribution or age-related changes, and may be less accurate for very muscular individuals, elderly people, or during pregnancy. Always discuss your personal BMI with your GP for context.
Should I be worried about being underweight?
Underweight (BMI below 18.5) can indicate nutritional deficiency, underlying illness, or other health concerns. If you're underweight, contact your GP to discuss your health. They can assess whether there's an underlying issue and advise on healthy weight gain if needed.
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.