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
18.5 Stone In Kg — Quick Conversion
18.5 stone is equal to 117.4 kg. If you're checking your weight in different units, our free weight converter above can help you switch between stone, pounds, and kilograms instantly. Understanding your weight in metric units makes it easier to track progress and compare health guidance, which is often given in kg on NHS resources and health charts.
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.
How To Convert Stone To Kilograms
To convert 18.5 stone to kg, multiply the stone value by 6.35029. The formula is: stone × 6.35029 = kilograms. So 18.5 × 6.35029 = 117.4 kg.
The reverse conversion from kilograms to stone divides by 6.35029. This standard kilogram to stone conversion is used across NHS resources, fitness tracking apps, and health calculators throughout the UK. You can also check nearby weight values in the conversion table below to find similar weights.
- 18 stone = 114.3 kg
- 18.25 stone = 115.9 kg
- 18.5 stone = 117.4 kg
- 18.75 stone = 119.0 kg
- 19 stone = 120.6 kg
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.
BMI And Health Context At 18.5 Stone
At 18.5 stone (117.4 kg), your health category depends on your height. For example, at the average UK adult height of 5ft 7in (170cm), a weight of 18.5 stone gives a BMI of approximately 40.6, which falls into the severely obese category according to NHS guidelines. Use our free BMI calculator above to check your personal BMI based on your exact height and weight. Even a modest weight loss of 5–10% can bring meaningful health improvements, including better blood pressure, improved blood sugar control, and reduced joint strain.
- 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 18.5 stone in kg exactly?
18.5 stone is exactly 117.4 kg. This uses the standard conversion factor where 1 stone equals 6.35029 kg. All UK weight converters use this same figure, so you'll see consistent results across health websites and NHS resources.
How do I convert stone to kilograms myself?
Multiply the stone value by 6.35029. For 18.5 stone: 18.5 × 6.35029 = 117.4 kg. To convert kg back to stone, divide by 6.35029. Our weight converter tool on this page does this instantly for any weight value.
Is 18.5 stone a healthy weight?
Whether 18.5 stone is healthy depends entirely on your height. At shorter heights, this weight may fall into the obese category; at taller heights, it may be lower. Use the BMI calculator above with your height to check your personal BMI and health category according to NHS guidelines.
What does 18.5 stone equal in pounds?
18.5 stone equals 259 pounds (lbs). Since 1 stone = 14 pounds, multiply: 18.5 × 14 = 259 lbs. Our weight converter lets you check any stone and pounds to lbs or kg instantly.
How much weight would I need to lose from 18.5 stone to reach a healthy BMI?
This depends on your height. For a 5ft 7in adult, reaching a healthy BMI of 24.9 would require a weight of approximately 12 stone 6lbs (79 kg) — a loss of about 6 stone. Your GP can advise on realistic targets for your individual circumstances and health.
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.