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
Calories for Weight Loss in Females — What You Need to Know
Weight loss for women fundamentally requires a calorie deficit — consuming fewer calories than your body burns. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for sustainable results, which typically means creating a deficit of around 500 calories per day. However, the right calorie target depends on your individual metabolism, activity level, current weight, and health status. For eligible women, prescription weight management options are now available in the UK alongside dietary changes, offering additional support beyond calorie counting alone.
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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.
Calorie Deficits and Weight Loss Medication in the UK
A sustainable calorie deficit of 500 kcal per day typically leads to losing approximately 0.5 kg per week. For women, typical daily calorie needs range from 1,800 to 2,200 kcal depending on age, height, weight, and activity level — so a weight loss target might be 1,300 to 1,700 kcal daily. The NHS emphasises that very low calorie diets (under 800 kcal daily) should only be followed under medical supervision.
For eligible women in the UK, prescription weight loss medications are now available:
- Mounjaro (tirzepatide) — dual GIP/GLP-1 injection, once weekly. Clinical trials showed average weight loss of 15–21% body weight when combined with reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — GLP-1 injection, once weekly. Average weight loss approximately 15% body weight in clinical trials.
- Saxenda (liraglutide) — GLP-1 injection, once daily. Available for women with BMI 30 or above, or BMI 27+ with weight-related health conditions.
These medications work by helping reduce appetite and cravings, making it easier to maintain a calorie deficit alongside your chosen diet. Our free GLP-1 weight loss calculator can help you estimate potential weight loss at different doses if you're considering prescription options.
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.
NHS Eligibility and How to Access Weight Loss Support
Women may be eligible for prescription weight management in the UK if they have a BMI of 30 or above, or BMI of 27–29.9 with at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). Access through the NHS is via specialist tier 3 weight management services — your GP can refer you, though waiting lists vary significantly by region. Alternatively, private online prescribing is available following a clinical assessment without an NHS referral. Use our free BMI calculator to check your personal BMI, then speak with your GP about whether prescription support combined with calorie management would suit your situation. They can discuss your individual calorie needs, dietary approach, and whether medication might help you achieve sustainable weight loss.
- 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.
How many calories should a woman eat daily to lose weight?
This varies individually based on age, height, current weight, and activity level. A typical starting point is 1,300–1,700 kcal daily to create a 500 kcal deficit, aiming for 0.5 kg weekly loss. Your GP or a registered dietitian can advise on your personal needs. Never drop below 1,200 kcal daily without medical supervision.
Is 1,200 calories per day safe for women?
The NHS considers 1,200 kcal per day a low calorie diet and recommends medical supervision at this level. Very low calorie diets (under 800 kcal) are only safe under medical guidance. Most women should aim for 1,400–1,800 kcal daily for sustainable, healthy weight loss.
Can prescription weight loss medication replace calorie counting?
No. Mounjaro, Wegovy, and Saxenda are prescribed alongside a reduced-calorie diet and increased physical activity — not instead of them. These medications help reduce appetite and cravings, making it easier to maintain a calorie deficit and healthier eating habits.
How do I know if I'm eligible for prescription weight loss treatment in the UK?
You may be eligible if you have a BMI of 30 or above, or BMI 27–29.9 with a weight-related health condition. Use our free BMI calculator to check your BMI, then speak with your GP about referral to specialist services or discuss private options. A prescriber will assess whether medication is suitable for you.
What's the difference between NHS and private weight loss medication access?
NHS access is through specialist tier 3 services (requires GP referral, regional waiting lists apply). Private access is through online prescribing following a clinical assessment, without an NHS referral and typically faster. Both require a prescription and clinical assessment. Costs vary by route and medication dose.
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.