Written by Tou Calo Nutrition Team · Vulcan Labs · Updated July 2026.
To figure out weight loss percentage, divide the amount of weight you have lost by your starting weight, then multiply by 100. That is the complete formula. This guide walks through it with worked examples in both kg and lbs, a reference table for common starting weights, and an explanation of what a healthy weight loss percentage looks like over time.
The formula: Weight loss % = (Starting weight − Current weight) ÷ Starting weight × 100
Example: Started at 85 kg, now 79 kg → (85 − 79) ÷ 85 × 100 = 7.1%
In this guide
- The weight loss percentage formula
- Worked examples — kg and lbs
- Reference table — weight loss % by starting weight
- What is a good weight loss percentage?
- Weight loss % vs body fat % — the difference
- FAQ
The weight loss percentage formula
The formula has three steps:
- Subtract current weight from starting weight — this gives you the amount lost
- Divide that number by your starting weight
- Multiply by 100 — this converts the decimal to a percentage
Weight loss % = (Starting weight − Current weight) ÷ Starting weight × 100
The unit you use does not matter — as long as both starting weight and current weight are in the same unit (both in kg, or both in lbs), the percentage will be identical either way.
Worked examples
Example 1 — kilograms
Starting weight: 90 kg · Current weight: 81 kg
(90 − 81) ÷ 90 × 100 = 9 ÷ 90 × 100 = 10%
Example 2 — pounds
Starting weight: 200 lbs · Current weight: 185 lbs
(200 − 185) ÷ 200 × 100 = 15 ÷ 200 × 100 = 7.5%
Example 3 — small loss
Starting weight: 75 kg · Current weight: 72 kg
(75 − 72) ÷ 75 × 100 = 3 ÷ 75 × 100 = 4%
Reference table — weight loss % by starting weight
How much weight in kg equals a given percentage, depending on starting weight:
| Starting weight | 5% loss = | 10% loss = | 15% loss = |
|---|---|---|---|
| 60 kg | 3 kg | 6 kg | 9 kg |
| 70 kg | 3.5 kg | 7 kg | 10.5 kg |
| 80 kg | 4 kg | 8 kg | 12 kg |
| 90 kg | 4.5 kg | 9 kg | 13.5 kg |
| 100 kg | 5 kg | 10 kg | 15 kg |
| 120 kg | 6 kg | 12 kg | 18 kg |
What is a good weight loss percentage?
Clinical research and health guidelines generally consider the following ranges meaningful:
| Weight loss % | Clinical significance |
|---|---|
| 1–3% | Modest initial progress — meaningful over 4–8 weeks |
| 5–10% | Associated with measurable health improvements — blood pressure, cholesterol, blood glucose |
| 10–15%+ | Significant — associated with major improvements in metabolic markers |
A 5–10% reduction in body weight is the benchmark most commonly cited in clinical guidelines for meaningful health improvement. In practical terms, for a 90 kg person that is 4.5–9 kg. The rate at which you reach that percentage matters as much as the number itself — a sustainable rate of 0.5–1% of body weight per week is generally recommended.
To understand the calorie deficit required to reach a given weight loss percentage, use our calorie deficit calculator. To find your starting calorie baseline, use our BMR calculator and TDEE calculator.
Weight loss % vs body fat % — the difference
These are two different measurements that are often confused:
| Metric | What it measures | How to calculate |
|---|---|---|
| Weight loss % | How much of your starting body weight you have lost | (Start − Current) ÷ Start × 100 |
| Body fat % | What proportion of your total body weight is fat tissue | Requires measurements — use our body fat calculator |
Weight loss percentage is a useful tracking metric — simple to calculate and meaningful relative to your own body. Body fat percentage goes deeper, distinguishing fat loss from muscle loss. Both are worth tracking over time for a complete picture of progress.
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Download Free →Figure weight loss percentage — FAQ
How do I figure out my weight loss percentage?
Use this formula: (Starting weight − Current weight) ÷ Starting weight × 100. For example, if you started at 80 kg and now weigh 74 kg: (80 − 74) ÷ 80 × 100 = 7.5%. The unit does not matter — as long as both weights are in the same unit, the percentage is the same whether you use kg or lbs.
What is a healthy weight loss percentage per week?
Most health guidelines recommend losing 0.5–1% of body weight per week as a sustainable rate. For a 90 kg person, that is 0.45–0.9 kg per week. Rates faster than 1% per week over extended periods increase the risk of muscle loss, nutrient deficiencies and metabolic adaptation. Use our calorie deficit calculator to find the daily calorie target that supports this rate for your specific body weight.
Is 10% weight loss significant?
Yes — a 10% reduction in body weight is considered clinically significant by most health organisations. Research consistently shows that losing 5–10% of starting body weight is associated with measurable improvements in blood pressure, cholesterol levels and blood glucose regulation. For a 90 kg person, 10% is 9 kg. For an 80 kg person, it is 8 kg.
Does weight loss percentage work the same in kg and lbs?
Yes — the percentage is identical regardless of unit because the unit cancels out in the calculation. (80 kg − 72 kg) ÷ 80 kg × 100 = 10%, and the same calculation in lbs produces the same percentage. The only requirement is that both weights use the same unit.
What is the difference between weight loss percentage and body fat percentage?
Weight loss percentage measures how much of your starting body weight you have lost — it includes all tissue, including water, muscle and fat. Body fat percentage measures what proportion of your current total body weight is fat tissue specifically. Both are useful tracking metrics. Weight loss percentage is simpler to calculate from scale weight alone. Body fat percentage requires body measurements — use our body fat calculator to find yours.
Disclaimer: Weight loss percentage is a tracking metric based on scale weight. It does not distinguish between fat loss, muscle loss and water changes. For a fuller picture of body composition change, track body fat percentage alongside scale weight.
Written by Tou Calo Nutrition Team — Vulcan Labs
The team behind Tou Calo AI Calorie Counter.
Related tools:
BMR Calculator — your resting calorie baseline
TDEE Calculator — your total daily calorie burn
Calorie Deficit Calculator — your fat loss target
Body Fat Calculator — fat mass and lean mass
calories and macros in 3 seconds.