Use this independent UK weight-loss progress calculator to work out how much weight you have lost from your starting weight. It supports kilograms and UK stone/pounds and shows total loss, percentage body-weight change and equivalent units. It is not an official NHS calculator.

How much weight have I lost?

How the weight-loss calculation works

The basic calculation is starting weight minus current weight. Percentage body-weight change is calculated as the amount lost divided by starting weight, multiplied by 100. Percentage change can make progress easier to compare when starting weights differ.

Worked example

If you started at 100 kg and now weigh 92 kg, you have lost 8 kg. The percentage loss is (8 ÷ 100) × 100 = 8%. The calculator also converts the difference into pounds and stone/pounds.

Tracking weight safely

NHS weight-management advice says people trying to lose weight can aim for around 0.5 to 1 kg (1 to 2 lb) per week. Day-to-day weight can move because of hydration, food, clothing and other factors, so a trend over time is usually more useful than a single reading.

This calculator measures progress only. It does not decide whether you should lose weight or set a personal target. For adults, BMI and waist-to-height ratio can provide additional context, although BMI also has limitations.

Kilograms, pounds and stone

One pound is exactly 0.45359237 kg and one stone is 14 pounds. The calculator converts internally using these fixed relationships, so you can enter weights in the format you normally use in the UK.

Important considerations

  • Weight alone does not show the difference between body fat, muscle and fluid.
  • Rapid or unexplained weight loss should not be treated as a calculator goal; seek healthcare advice if you are concerned.
  • Pregnancy, eating disorders, some illnesses and some medicines require individual advice rather than generic weight-loss targets.
  • Use measurements taken under reasonably similar conditions when comparing progress.

Authoritative sources

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Frequently asked questions

How do I calculate how much weight I have lost?

Subtract your current weight from your starting weight. A positive difference means weight loss; if the current weight is higher, the calculator reports weight gain instead of showing a misleading negative loss.

How do I calculate percentage weight loss?

Divide the weight lost by your starting weight and multiply by 100. For example, losing 5 kg from 100 kg is a 5% reduction.

Can I use stone and pounds?

Yes. Select stone and pounds and enter each weight using separate stone and pound fields.

Is this an official NHS weight-loss calculator?

No. This is an independent calculator that links to NHS guidance for general weight-management information.

This tool is for general information and progress tracking, not diagnosis or personalised medical advice.

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