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Used by Mounjaro & Wegovy patients across the UK

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
Get the guide + free tracker — £1.99

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GLP-1 Medication Guide — 11 chapters, 100+ pages, NHS-aligned with free 52-week weight loss tracker calendar
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What is 81.5 kg in stones and pounds?

81.5 kilograms is equal to 12 stone 11.6 pounds. This conversion uses the standard formula where one stone equals exactly 6.35029 kg. If you prefer just pounds, 81.5 kg converts to approximately 179.7 lbs. Our free weight converter above makes it easy to switch between kilograms, stones, and pounds instantly. Understanding your weight in both metric and imperial measurements is useful whether you're tracking health progress, discussing weight with your GP, or comparing UK health guidelines.

10,000+ calculations today · NHS-aligned thresholds · 100% free

26%of UK adults are living with obesityNHS Digital, 2023
64%of adults in England are overweight or obeseHealth Survey for England
£6.5bnannual cost of obesity to the NHSPublic Health England
4.7Mpeople in England eligible for weight loss drugsNICE estimates, 2024

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.

Below 18.5Underweight
18.5 – 24.9Healthy
25 – 29.9Overweight
30+Obese

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.

Conversion formula and nearby weight values

To convert kilograms to stone, divide the kilogram value by 6.35029. So 81.5 kg ÷ 6.35029 = 12.84 stone. To express this in stone and pounds, multiply the decimal by 14 (since one stone contains 14 pounds): 0.84 × 14 = 11.6 lbs, giving you 12 stone 11.6 pounds.

Here are weight values near 81.5 kg for quick reference:

  • 79 kg = 12 stone 6.4 lbs
  • 80 kg = 12 stone 8.1 lbs
  • 81.5 kg = 12 stone 11.6 lbs
  • 83 kg = 13 stone 1.6 lbs
  • 85 kg = 13 stone 5.2 lbs

This conversion follows the metric to imperial weight standard used across the UK. You can also use our weight converter tool above to explore any kilogram value instantly.

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How It Works

Three simple steps to understand your weight and take action.

1Check Your BMI

Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.

2Explore Your Options

If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.

3Track Your Progress

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 healthy weight context for 81.5 kg

At 81.5 kg, your BMI depends on your height. For example, at an average UK adult height of 170 cm (5ft 7in), a weight of 81.5 kg gives a BMI of approximately 28.2, which falls in the overweight category (BMI 25–29.9) according to NHS guidelines. At 175 cm (5ft 9in), the same weight gives a BMI of approximately 26.6, still overweight. At 165 cm (5ft 5in), it would be approximately 29.9, near the upper boundary of overweight.

The NHS healthy weight range for most adults is a BMI between 18.5 and 24.9. Use our free BMI calculator above to find your personal BMI and healthy weight range at your actual height. If you have concerns about your weight and health, your GP can offer personalised guidance.

Mounjaro (Tirzepatide)
  • 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
Read our full Mounjaro guide →
Wegovy (Semaglutide)
  • 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
Read our full Wegovy guide →

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.

FeatureMounjaroWegovy
Drug classDual GIP/GLP-1 agonistGLP-1 agonist
Active ingredientTirzepatideSemaglutide
Avg. weight loss15–22.5%12–17%
Key trialSURMOUNT-1 (2022)STEP 1 (2021)
Max dose15 mg weekly2.4 mg weekly
Escalation period20–32 weeks16–20 weeks
AdministrationWeekly injection (pen)Weekly injection (pen)
NHS availabilityPrivate prescription onlyNHS & private
Approx. private cost£150–£250/month£150–£300/month
Common side effectsNausea, diarrhoea, constipationNausea, 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.

Standard eligibility
  • BMI of 30 or above (obese)
  • Age 18 or over
  • No contraindicated conditions
  • Committed to lifestyle changes
With comorbidities
  • 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.

How do I convert 81.5 kg to stones and pounds manually?

Divide 81.5 by 6.35029 to get 12.84 stone. Take the decimal (0.84) and multiply by 14 to get pounds: 0.84 × 14 = 11.6 lbs. So 81.5 kg = 12 stone 11.6 pounds. Our free weight converter above does this instantly.

Is 81.5 kg considered a healthy weight?

It depends on your height and individual health factors. At average UK heights, 81.5 kg typically falls in the overweight category (BMI 25–29.9). The NHS recommends a BMI of 18.5–24.9 for most adults. Use our BMI calculator to check your personal BMI and discuss healthy targets with your GP.

What is 81.5 kg in just pounds?

81.5 kg equals approximately 179.7 pounds (lbs). However, in the UK, weight is more commonly expressed in stone and pounds, so 12 stone 11.6 lbs is the standard way to state this weight in British measurements.

How much weight loss would move me from 81.5 kg to a healthy BMI?

The amount depends on your height and target BMI. Generally, losing 5–10% of body weight can have meaningful health benefits. At 81.5 kg, that's 4–8 kg of loss. Your GP or a weight management programme can advise on realistic, sustainable targets for your individual situation.

Is 81.5 kg overweight for everyone?

No. Whether 81.5 kg is overweight depends on your height, age, sex, and muscle mass. BMI is a screening tool and has limitations—it doesn't distinguish between muscle and fat. For personalised advice about your weight and health, consult your GP or use our BMI calculator to check your individual BMI.

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.

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