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's 66.6kg in Stone and What Does It Mean for Your BMI?
66.6kg is equivalent to 10 stone and 6.6 pounds in UK measurements. However, your BMI (which tells you whether this weight is healthy for you) depends entirely on your height. At different heights, 66.6kg can fall into different NHS weight categories — from healthy weight to overweight. Use our free BMI calculator above to find your exact BMI, or read on to see example BMI values at common UK heights.
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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.
66.6kg BMI at Different Heights
To convert 66.6kg to stone and understand your health context, here's how this weight translates to BMI across common UK heights:
- At 160cm (5ft 3in): BMI = 25.9 — falls in the overweight range (25.0–29.9)
- At 165cm (5ft 5in): BMI = 24.5 — falls in the healthy weight range (18.5–24.9)
- At 170cm (5ft 7in): BMI = 23.1 — falls in the healthy weight range
- At 175cm (5ft 9in): BMI = 21.7 — falls in the healthy weight range
- At 180cm (5ft 11in): BMI = 20.6 — falls in the healthy weight range
As you can see, 66.6kg represents a healthy weight for taller adults, but may be slightly overweight for shorter adults. The BMI calculator on this page will give you your personal BMI instantly — just enter your height to check where you fall on NHS guidelines.
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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.
Understanding BMI Categories and Limitations
The NHS uses these weight categories based on BMI:
- Underweight: BMI below 18.5
- Healthy weight: BMI 18.5–24.9
- Overweight: BMI 25.0–29.9
- Obese: BMI 30.0 and above
However, BMI has important limitations. It doesn't distinguish between muscle and fat — athletes may have a high BMI but low body fat. It also doesn't account for where fat is stored. For a complete picture, your GP may also consider your waist circumference and overall health. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds due to higher health risks at the same BMI.
- 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 66.6kg in stone and pounds exactly?
66.6kg converts to 10 stone and 6.6 pounds (10st 6.6lbs). To convert kilograms to stone, divide the kilogram value by 6.35029. Our free weight converter above lets you instantly convert between kg, stone, and pounds for any weight.
Is 66.6kg a healthy weight?
Whether 66.6kg is healthy depends on your height. Using our BMI calculator, you can enter your exact height to see your personal BMI and which NHS category you fall into. At taller heights, 66.6kg is typically healthy; at shorter heights, it may be overweight.
How do I calculate my BMI if I weigh 66.6kg?
BMI = weight (kg) ÷ height (metres)². If you're 1.70m tall, your BMI would be 66.6 ÷ (1.70)² = 23.1 (healthy weight). Use our free BMI calculator on this page to find your exact BMI by entering your height.
What does overweight mean in terms of health?
A BMI between 25.0–29.9 is classified as overweight by the NHS. This increases health risks including type 2 diabetes, high blood pressure, and heart disease. Your GP can advise on lifestyle changes or, if appropriate, weight management options. Even a 5–clinically studied weight loss can reduce these risks significantly.
Should I try to lose weight if I'm 66.6kg?
This depends on your height, overall health, and any weight-related conditions. Your GP is the best person to discuss whether weight loss would benefit you personally. If you're interested in weight management options, your GP can refer you to NHS services or discuss other approaches tailored to your situation.
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.