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
Weight Maintenance Calculator — Keep Your Healthy Weight
Maintaining a healthy weight after losing weight is just as important as the weight loss itself. A weight maintenance calculator helps you work out exactly how many calories you need each day to stay at your current weight, based on your age, height, activity level, and metabolism. Whether you've reached your target weight through diet, exercise, or with support from prescription medications, understanding your maintenance needs is key to long-term success. Use our free BMI calculator and weight converter to track where you are now, then calculate the daily calories required to keep you there.
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 Does Weight Maintenance Work in the UK?
Weight maintenance means consuming roughly the same number of calories as your body burns each day — your Total Daily Energy Expenditure (TDEE). This is different for every person and depends on several factors:
- Basal Metabolic Rate (BMR): calories your body burns at rest, influenced by age, sex, height, weight, and genetics
- Activity level: how much exercise and daily movement you do
- Occupation: sedentary desk jobs vs active roles burn different amounts
The NHS recommends that adult women aim for around 2,000 calories per day and adult men around 2,500 calories, but these are averages. Your personal maintenance calorie needs may be significantly higher or lower. A weight maintenance calculator accounts for your individual factors to give you a personalised figure. Once you know your TDEE, you can eat that amount daily to maintain your current weight without gaining or losing.
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.
UK Tools and Resources for Weight Management
MyWeightCheck provides several free tools to help with your weight maintenance journey. Our BMI calculator instantly shows whether your current weight is within a healthy range according to NHS guidelines — essential context for setting realistic maintenance goals. Our weight converter lets you switch between kg, stone, and pounds, making it easy to track progress in whichever units feel most natural to you. If you've used prescription weight loss treatment like Mounjaro or Wegovy to reach your target weight, our GLP-1 weight loss calculator shows what dose-related weight loss you achieved. For ongoing tracking, use our progress tracker to log weekly weigh-ins and spot any gradual upward drift early, when small adjustments are easiest to make. Always consult your GP or a registered dietitian if you need personalised advice about your specific maintenance needs.
- 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 difference between weight loss and weight maintenance calories?
Weight loss requires a calorie deficit (eating fewer calories than you burn), typically 500 kcal/day less for around 0.5 kg/week loss. Weight maintenance requires eating roughly the same number of calories as your body burns daily — your TDEE. You switch to maintenance calories once you reach your goal weight.
Can I maintain weight without counting calories?
Yes, many people maintain weight intuitively after reaching their goal, especially if they've developed healthy eating habits. However, tracking intake occasionally (weekly or monthly) helps spot weight drift early. Using a maintenance calculator gives you a baseline figure to refer back to if needed.
How does my activity level affect maintenance calories?
More physical activity increases your TDEE significantly. Someone with a sedentary job and no exercise burns far fewer calories than someone doing regular strength training and cardio. A maintenance calculator multiplies your BMR by an activity factor (sedentary, lightly active, moderately active, very active) to account for this.
What should I do if I start to gain weight during maintenance?
Small weight gains of 1–2 kg are normal fluctuation from water retention, food choices, or activity changes. If gain persists over 2–3 weeks, reduce daily intake by 100–200 calories or increase activity. Use our progress tracker to spot trends. If concerned, consult your GP.
Does prescription weight loss medication affect maintenance calorie needs?
If you've used GLP-1 medication like Mounjaro or Wegovy and have now stopped, your appetite hormones gradually normalise, which may increase your hunger. You may find you naturally need slightly more food to feel satisfied. Monitor this with our progress tracker and adjust intake as 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.