How Much Weight Have I Lost? Calculator
Whether you’ve been following a diet plan, hitting the gym, or simply making healthier choices — knowing exactly how much weight you’ve lost helps you stay motivated and on track. Our free calculator works in stones and pounds (the way most of us in the UK actually weigh ourselves), and shows you your total loss, percentage of body weight shed, BMI change, and weekly rate.
Weight Loss Calculator (Stones, Pounds & Kg)
Enter your starting weight (when you began your journey) and your current weight. Optionally add a goal weight to see your progress bar. All results include stones, pounds and kilograms.
How to Use This Weight Loss Calculator
- Choose your units — stones & lbs (UK default), kilograms, or pounds only.
- Enter your height — needed to calculate your BMI before and after.
- Add your starting weight — the weight you were when you began your journey.
- Add your current weight — what the scales say today.
- Set a goal weight (optional) — to see a progress bar showing how far you’ve come.
- Select the time period — how long you’ve been losing weight, so we can calculate your weekly rate.
What Your Results Mean
Total Weight Lost
This is the straightforward difference between your starting weight and current weight, shown in all three unit systems. It’s the headline number — the one that tells you how far you’ve come.
Weight Loss Percentage
Arguably more useful than the raw number. Losing 2 stone when you started at 20 stone (10%) is very different from losing 2 stone when you started at 10 stone (20%). The percentage puts your loss in context. Most health organisations consider 5–10% loss clinically significant.
Weekly Rate
How quickly you’re losing weight, averaged across your selected time period. The NHS recommends 1–2 lbs per week (about 0.5–1 kg). Faster than 2 lbs/week consistently may indicate you’re losing muscle alongside fat.
Estimated Calorie Deficit
Based on the principle that 1 lb of body fat contains roughly 3,500 calories, this estimates how many fewer calories you’ve been eating per day compared to your maintenance level. It’s an approximation — metabolism, activity, and body composition all affect the real number.
BMI Before & After
Your Body Mass Index at your starting weight and current weight. While BMI doesn’t account for muscle mass, seeing your category shift (e.g., from “Obese” to “Overweight,” or “Overweight” to “Healthy”) is a meaningful milestone worth celebrating.
What Is a Healthy Rate of Weight Loss?
According to the NHS and the British Dietetic Association:
- 1–2 lbs per week (0.5–1 kg) is considered safe and sustainable
- This means 1 stone every 7–14 weeks
- Losing faster than this increases the risk of muscle loss, gallstones, nutritional deficiencies, and metabolic slowdown
- Very low-calorie diets (under 800 kcal/day) should only be followed under medical supervision
Stones to Kilograms Conversion Chart
Since the UK uses stones and pounds while most of the world uses kilograms, here’s a quick reference:
| Stones | Pounds | Kilograms |
|---|---|---|
| 8 stone | 112 lbs | 50.8 kg |
| 9 stone | 126 lbs | 57.2 kg |
| 10 stone | 140 lbs | 63.5 kg |
| 11 stone | 154 lbs | 69.9 kg |
| 12 stone | 168 lbs | 76.2 kg |
| 13 stone | 182 lbs | 82.6 kg |
| 14 stone | 196 lbs | 88.9 kg |
| 15 stone | 210 lbs | 95.3 kg |
| 16 stone | 224 lbs | 101.6 kg |
| 17 stone | 238 lbs | 108.0 kg |
| 18 stone | 252 lbs | 114.3 kg |
| 19 stone | 266 lbs | 120.7 kg |
| 20 stone | 280 lbs | 127.0 kg |
Weight Loss Milestones Worth Celebrating
Weight loss is a marathon, not a sprint. These milestones help mark real progress:
- First half stone (7 lbs): Your clothes start fitting differently. You might notice your rings are looser.
- 5% body weight: Clinically significant. Blood pressure and blood sugar begin improving.
- 1 stone (14 lbs): Others start noticing. Your face shape changes. Energy levels improve.
- 10% body weight: Major health marker. Risk of type 2 diabetes drops significantly. Sleep quality improves.
- 2 stone (28 lbs): Wardrobe overhaul territory. You likely need smaller clothes.
- BMI category change: Moving from “Obese” to “Overweight” or “Overweight” to “Healthy” is a landmark moment.
- 3+ stone: Transformational. You look and feel like a different person. Joints feel better. Stamina is higher.