How Much Weight Have I Lost?
Two simple formulas answer this completely. Total lost = start weight minus current weight. Percentage lost = lost divided by start weight, times 100. Worked examples below in stone, lbs, and kg.
How to Work Out Your Total Weight Lost
Weigh yourself in whatever unit you started with, then subtract. If you started at 15 st 10 lb (99.79 kg) and now weigh 13 st 10 lb (87.09 kg), you have lost 2 stone (28 lb, 12.7 kg). The maths is the same in any unit.
Three illustrative examples, one per common UK unit:
| Start weight | Current weight | Total lost |
|---|---|---|
| 18 st 0 lb | 16 st 7 lb | 1 st 7 lb (21 lb / 9.53 kg) |
| 12 st 5 lb | 11 st 12 lb | 7 lb (0.5 st / 3.18 kg) |
| 95 kg | 86 kg | 9 kg (1 st 6 lb / 19.8 lb) |
Mixing units is the classic UK problem, your GP records kg, your scales show stone, your fitness app shows lb. Convert everything to one unit first with our kg to stone converter or the stone to kg chart. Reddit's r/loseit community has the same complaint constantly: users discover their "confusing" progress was just unit mismatch between apps.
How to Calculate Your Weight Loss Percentage
Percentage puts your loss in context. Losing 14 lb means something very different starting from 12 stone versus 20 stone. The formula is (weight lost ÷ starting weight) × 100.
Worked example: you lost 12.7 kg from a starting weight of 99.79 kg. Divide 12.7 by 99.79 to get 0.127, multiply by 100, and you have lost 12.7% of your starting weight. Calculator sites like weightlosspercentage.com and Chemist4U's UK guide use exactly this formula.
| Milestone | What it means |
|---|---|
| 5% lost | First clinically meaningful milestone, the level clinicians generally associate with measurable health improvements |
| 10% lost | Major milestone, often brings visible body composition change and further health benefits |
| 15%+ lost | Significant transformation territory |
Percentage is also the fair way to compare with others. Losing 10% is a bigger achievement from 14 stone than from 20 stone in absolute pounds, but the percentage makes progress comparable across body sizes, which is why weight-loss groups and research studies use it.
How to Track Your Progress Properly
The number most people get wrong is not the total, it is the trend. Daily scale noise (1 to 3 lb from water, food, and hormones) can hide real progress. Do this instead:
- Weigh weekly, same day, same time, morning after the toilet, before breakfast
- Use the same scale on a hard, flat floor
- Log it in one place, an app, a spreadsheet, or a notebook, and watch the 4-week trend
- Add measurements: waist, hips, and chest monthly, since daily fluctuations can mask fat loss the tape measure catches
- Take photos in the same clothes and lighting, they show change the scale misses
A note on unintentional weight loss: this guide is for deliberate weight loss. If you are losing weight without trying, especially more than 5% of your body weight in 6 to 12 months, speak to your GP, as it can signal an underlying condition.
What Counts as Good Progress?
The NHS recommends losing 1 to 2 lb (0.5 to 1 kg) per week. At that pace, losing a stone takes 7 to 14 weeks, and losing 5% of a 16-stone starting weight (11.2 lb) takes about 6 to 11 weeks. Slower than you hoped is still normal, faster than 2 lb per week usually means water and muscle rather than fat.
If the scale stalls for 2 to 3 weeks despite consistent effort, read our plateau guide before changing anything drastic. And if you want the full plan for losing a stone safely, start with how to lose a stone, then check your BMI for context.
Frequently Asked Questions
How do I work out how much weight I have lost?
Subtract your current weight from your starting weight, using the same units. For example, 16 stone minus 14 stone 7 lb equals 1 stone 7 lb lost. Then divide the amount lost by your starting weight and multiply by 100 for your percentage lost.
How do I convert my weight loss into stone?
Divide the total pounds lost by 14 to get stone. So 21 lb lost is 1.5 stone. For kilograms, divide by 6.3503 to get stone, or multiply stone by 6.3503 to get kilograms.
What is a good percentage of weight loss?
Losing 5% of your starting weight is widely used by clinicians as the first meaningful milestone, with further benefits at 10%. A 5% loss from 16 stone, for example, is 11.2 lb (0.8 stone).
How often should I weigh myself when tracking weight loss?
Weigh once a week, at the same time and under the same conditions (morning, after the toilet, before breakfast). Daily weigh-ins are fine if you can ignore the noise, but the weekly trend is what counts.
I have lost weight but the scale stalled. Have I stopped losing fat?
Not necessarily. Water, glycogen, sodium, and digestion can mask fat loss on the scale for weeks. Check your measurements, photos, and how clothes fit before concluding progress has stopped.