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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How To Compute Weight — A Complete UK Guide
Computing your weight means more than just knowing the number on the scales — it's about understanding what that weight means for your health. In the UK, we use stone, pounds, and kilograms to measure body weight, and converting between these units is straightforward once you know the formulas. This guide explains exactly how to compute weight, convert between measurements, and use that information to assess whether you're at a healthy weight according to NHS guidance. Whether you need to convert kilograms to stone or calculate your BMI, we'll walk you through each step.
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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.
How To Calculate Your Weight in Different Units
Computing your weight in different measurements is simple once you understand the conversion factors. To convert kilograms to stone: divide the weight in kg by 6.35029. For example, 70kg ÷ 6.35 = 11 stone. To convert kg to pounds: multiply by 2.20462 — so 70kg × 2.20462 = 154.3 lbs. To convert stone to pounds: multiply by 14 exactly, since one stone equals 14 pounds. If you have weight in stone and pounds (e.g. 11 stone 2 lbs), convert to kg using this formula: (stone × 6.35029) + (lbs × 0.453592) = kg.
Use our free weight converter above to instantly switch between kg, stone, and pounds — no mental maths required. Our BMI calculator will also help you understand whether your computed weight falls into a healthy range according to NHS guidance.
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.
Computing Your BMI and Healthy Weight Range
Once you've computed your weight, the next step is understanding what it means for your health. The simplest way is to calculate your Body Mass Index (BMI), which relates your weight to your height. The formula is: BMI = weight (kg) ÷ height (m)². According to NHS guidelines, a healthy BMI for UK adults is between 18.5 and 24.9. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the recommended range is 18.5 to 22.9 due to higher health risks at higher BMI levels.
To find your healthy weight range for your height, multiply your height (in metres, squared) by 18.5 for the lower bound and 24.9 for the upper bound. For a person 1.73m tall, the healthy range is approximately 55–75 kg (8st 10lbs to 11st 10lbs). Remember, BMI is a useful screening tool but has limitations — it doesn't account for muscle mass or where fat is stored.
- 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's the easiest way to compute my weight in stone if I only know it in kilograms?
Divide your weight in kg by 6.35029 to get stone. For example, 80kg ÷ 6.35 = 12.6 stone, which is 12 stone 8.4 lbs. Our free weight converter on this page will do this instantly for you — just enter your weight and select the units you want to convert between.
How do I compute whether my weight is healthy according to NHS guidance?
Calculate your BMI using the formula: weight (kg) ÷ height (m)². NHS guidelines classify a BMI of 18.5–24.9 as healthy weight. Use our free BMI calculator above to compute your BMI instantly and see exactly which health category you fall into based on your height and weight.
If I weigh 100kg, how do I compute that in stone and pounds?
Divide 100kg by 6.35 to get 15.75 stone, which equals 15 stone 10.5 lbs. You can also multiply 100 by 2.20462 to get 220.5 lbs. Our weight converter does both calculations instantly if you'd prefer to use the tool rather than manually computing the conversion.
What's the difference between computing weight in UK stone versus kilograms?
Stone is an older imperial unit used mainly in the UK for body weight — one stone equals 14 pounds or 6.35 kg. Kilograms are the metric standard used by the NHS and most of the world. Both measure exactly the same thing; they're just different units. NHS health guidance often uses kg, but many UK people prefer stone for personal weight tracking.
How do I compute healthy weight loss — how much should I lose per week?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week for sustainable, healthy weight loss. To lose 0.5kg per week, you need a calorie deficit of roughly 500 kcal per day. Our free progress tracker lets you log your weight weekly and see your loss trajectory — a valuable way to monitor whether you're computing safe, sustainable progress towards a healthier weight.
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.