Free Weight Loss Calculator UK

Weight Loss Calculator UK | BMI, Calorie Deficit & Goal Calculator | Bury Healthcare

Free Weight Loss Calculator UK

Calculate your BMI, calorie deficit, and weight loss timeline with our professional calculator. Get personalised results in stones and pounds with expert guidance from qualified pharmacists.

Steady, safe weight lossA healthy 1–2 lbs per weekStartGoal ✓Wk 0Wk 4Wk 8Wk 12

How Much Weight Have I Lost?

Enter your starting weight and your weight today to work out how much weight you have lost, in stones and pounds, in pounds, in kilograms, and as a percentage of your starting weight.

0Lost in stones & pounds
0Lost in pounds
0Lost in kilograms
0Of your starting weight

BMI Calculator (Stones & Pounds)

0 Your BMI

Weight Loss Goal Calculator

0 Weeks to Goal
0 Daily Calorie Deficit

What the NHS Says About Healthy Weight Loss

These calculators use the same measures the NHS uses. Here is how the NHS interprets them, so you can put your own numbers in context.

NHS BMI categories for adults

  • Below 18.5 – underweight
  • 18.5 to 24.9 – healthy weight
  • 25 to 29.9 – overweight
  • 30 and above – obese

BMI is a screening tool, not a diagnosis. The NHS notes that it is less reliable if you are very muscular, and it is not used in the same way during pregnancy. Adults of Black African, African-Caribbean and South Asian family background are advised to use lower thresholds — a BMI of 23 or above already indicates increased health risk, and 27.5 or above indicates high risk.

How fast should you lose weight?

The NHS recommends losing weight at a steady 0.5kg to 1kg a week (about 1lb to 2lb). That usually means eating around 600 calories a day fewer than you burn. Losing faster than this is harder to sustain, and more of what you lose tends to be muscle and water rather than fat.

At 1lb a week, a stone takes roughly fourteen weeks. Use the weight lost calculator above to check your actual rate against that, rather than against a number on a chart.

When to see your GP

Speak to your GP or a pharmacist if:

  • your BMI is 30 or above (or 27.5 or above if you are of South Asian, Chinese, Black African or African-Caribbean background)
  • you are losing weight without trying — this always needs checking
  • your weight is affecting your breathing, joints, sleep or mobility
  • you have a weight-related condition such as type 2 diabetes, high blood pressure or sleep apnoea

Your GP can refer you to an NHS weight management service. If your BMI is 40 or above, or 35 or above alongside a weight-related condition, you may be eligible for a specialist NHS service.

This page is information, not medical advice. The figures here follow current NHS guidance on healthy weight and safe rates of weight loss. If you are unsure what is right for you, speak to your GP, or to one of our pharmacists.

Understanding Your Weight Loss Results

BMI Categories

Underweight: Below 18.5
Normal: 18.5-24.9
Overweight: 25-29.9
Obese: 30 and above

Safe Weight Loss Rate

Health professionals recommend losing 1-2 pounds per week. This sustainable approach helps preserve muscle mass and reduces the risk of nutritional deficiencies.

Calorie Deficit Explained

To lose 1 pound, you need a deficit of 3,500 calories. A 500-calorie daily deficit equals 1 pound per week, achievable through diet and exercise combined.

Professional Support

Our qualified pharmacists can help with weight loss medication, monitoring, and personalised advice to support your weight loss journey safely and effectively.

Important Medical Advice

This weight loss calculator provides estimates based on general formulas. Individual results may vary based on metabolism, medical conditions, age, and activity level. For personalised weight loss plans and medical supervision, consult our qualified pharmacists. Always seek professional medical advice before starting any weight loss programme, especially if you have underlying health conditions.

Daily Calorie Calculator (BMR & TDEE)

See how many calories you burn each day and how much to eat to lose weight safely.

0BMR – calories burned at rest
0Maintenance calories (TDEE)
0To lose 1 lb/week, aim for this many a day

Weight Loss Calculator FAQs

How do I work out how much weight I have lost?
Subtract your current weight from your starting weight. The weight lost calculator at the top of this page does it for you and shows the answer four ways: in stones and pounds, in pounds, in kilograms, and as a percentage of your starting weight. Enter your figures in whichever units you weigh yourself in.
How much weight have I lost if I started at 15 stone and now weigh 13 stone 2 pounds?
You have lost 2 stone 2 pounds, which is 30 pounds or 13.6 kilograms. That is about 14% of your starting body weight. Percentage is often a more useful measure than the raw number, because losing 5% of your starting weight is the point at which the NHS says health benefits usually start to show.
How many pounds have I lost?
Work in pounds throughout: multiply your starting stones by 14 and add the pounds, do the same for your weight today, then subtract. Fourteen pounds make one stone. The calculator above handles the conversion, so you can enter stones and pounds and read the answer straight off in pounds.
How do I calculate weight loss in stones and pounds?
Convert both weights to pounds first, subtract, then divide the difference by 14. The whole number is your stones and the remainder is your pounds. Converting first avoids the common mistake of subtracting stones and pounds separately, which gives the wrong answer whenever the pounds figure of your current weight is higher than your starting one.
How do I convert my weight between stones, pounds and kilograms?
One stone is 14 pounds, and one kilogram is about 2.2 pounds. So one stone is roughly 6.35 kilograms. The calculator at the top of this page accepts either stones and pounds or kilograms, and always shows the result in both, so you do not need to convert anything by hand.
What percentage of my body weight have I lost?
Divide the weight you have lost by your starting weight, then multiply by 100. Losing 1 stone from a starting weight of 14 stone is about 7%. The NHS and NICE regard a 5% to 10% loss of starting body weight as clinically meaningful, because that is where improvements in blood pressure, blood sugar and cholesterol tend to appear.
Is this weight loss calculator free?
Yes. Every calculator on this page is free to use, there is no sign-up, and nothing you enter is stored or sent anywhere. The figures are worked out in your own browser.
Does the NHS have a weight loss calculator?
The NHS publishes a BMI calculator and healthy-weight guidance rather than a weight-lost calculator. The tools on this page use the same NHS thresholds: a healthy BMI of 18.5 to 24.9, and a safe weight loss rate of 0.5kg to 1kg, or 1lb to 2lb, a week. See the NHS section above for how those figures are applied.
What is a healthy rate of weight loss?
The NHS recommends losing 0.5kg to 1kg a week, which is about 1lb to 2lb. That usually means eating around 600 calories a day fewer than you burn. Faster loss is harder to keep off, and a greater share of it comes from muscle and water rather than fat.
How accurate is the weight loss calculator?
The weight-lost arithmetic is exact. The calorie and BMI figures are estimates: BMI does not distinguish muscle from fat, and calorie needs are based on population averages that can be out by a few hundred calories a day for any individual. Weigh yourself at the same time of day, in similar clothing, and judge progress over weeks rather than days.
How do I calculate my calorie deficit for weight loss?
Work out your maintenance calories with the daily calorie calculator on this page, then subtract the deficit you want. Roughly 3,500 calories equal one pound of fat, so a 500 calorie daily deficit gives about 1lb a week and a 1,000 calorie deficit about 2lb. Do not go below 1,500 calories a day for men or 1,200 for women without medical supervision.

Need Professional Weight Loss Support?

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