Weight Loss Percentage Calculator
Calculate exactly what percentage of your starting body weight you've lost. Track your progress with our milestone table showing 5%, 10%, 15%, and 20% goals.
How to Use
- Choose your unit (lbs or kg) using the toggle.
- Calculate % Lost tab: Enter your starting weight and current weight. The calculator shows the percentage lost, weight lost, and a milestone table.
- Find Target Weight tab: Enter your starting weight and the percentage you want to lose. The calculator shows your target weight and the weight you need to lose.
- Results update as you type.
What You'll Discover
- Percentage lost — how much of your starting weight you have lost, to two decimal places. A negative number means you have gained weight.
- Weight lost — the difference between your starting and current weight, in the unit you picked (lbs or kg).
- Milestone table — your target weight for 5%, 10%, 15% and 20% loss, with each one marked "Reached" or showing how much is left to go.
- Target weight — on the second tab, the weight you would be at after losing a chosen percentage, and how many lbs or kg that is.
The calculator works the same in pounds and kilograms. The percentage does not change with the unit, so 10% is 10% whichever scale you use.
Formula
% Weight Lost:
% Lost = ((Starting Weight − Current Weight) ÷ Starting Weight) × 100
Target Weight (Find Target tab):
Target Weight = Starting Weight × (1 − Target% ÷ 100)
Weight to Lose:
Weight to Lose = Starting Weight − Target Weight
Always divide by your starting weight, not your current weight. Dividing by the current weight makes the result look bigger than it is: 20 lbs off 200 lbs is a 10% loss, but 20 ÷ 180 would wrongly suggest 11.11%.
Examples
| Starting Weight | Current Weight | % Lost | Weight Lost |
|---|---|---|---|
| 200 lbs | 190 lbs | 5.00% | 10 lbs |
| 200 lbs | 180 lbs | 10.00% | 20 lbs |
| 250 lbs | 212.5 lbs | 15.00% | 37.5 lbs |
| 100 kg | 85 kg | 15.00% | 15 kg |
| 180 lbs | 162 lbs | 10.00% | 18 lbs |
Why Track Weight Loss as a Percentage
The same number of pounds means different things for different people. A percentage puts your progress on the same scale as everyone else's, whatever your starting weight.
| Starting weight | 10 lbs lost is |
|---|---|
| 150 lbs | 6.67% |
| 200 lbs | 5.00% |
| 250 lbs | 4.00% |
| 300 lbs | 3.33% |
Percentages are also how health guidance tends to talk about weight loss. The CDC notes that even a modest loss of 5 to 10 percent of total body weight is likely to bring health benefits, such as improvements in blood pressure, blood cholesterol and blood sugar. For a 200 lb person, 5% is 10 lbs.
On pace, the CDC says people who lose weight gradually and steadily, about 1 to 2 pounds a week, are more likely to keep it off. At 200 lbs, 2 lbs is 1% of body weight.
This calculator is for information only and is not medical advice. Talk to a doctor or registered dietitian before starting a weight loss plan, especially if you are pregnant, have a health condition, take medication, or are losing weight without trying.
Weight Loss Milestones by Starting Weight
The milestone table in the calculator uses your own numbers. This chart shows the same targets for a few common starting weights.
| Milestone | From 150 lbs | From 200 lbs | From 250 lbs | From 100 kg |
|---|---|---|---|---|
| 5% lost | 142.5 lbs | 190 lbs | 237.5 lbs | 95 kg |
| 10% lost | 135 lbs | 180 lbs | 225 lbs | 90 kg |
| 15% lost | 127.5 lbs | 170 lbs | 212.5 lbs | 85 kg |
| 20% lost | 120 lbs | 160 lbs | 200 lbs | 80 kg |
Every milestone is measured from the same starting weight. That is why the gaps are equal: each extra 5% from 200 lbs is another 10 lbs.
Why Weight Loss Percentages Don't Simply Add Up
Percentages behave differently depending on what you divide by. Three situations trip people up.
Two losses of 10% are not 20%
If you lose 10% from 200 lbs, you reach 180 lbs. Losing another 10% of 180 takes you to 162 lbs. From your original 200 lbs, that is 19%, not 20%. This calculator always measures from your starting weight, so it reports the true 19%.
Regaining takes a smaller percentage
Going from 200 lbs to 180 lbs is a 10% loss. Going back from 180 lbs to 200 lbs is an 11.11% gain, because the gain is measured from the lower weight. If you track a regain, enter your original starting weight and you will see a smaller "% lost" rather than a new percentage.
Weekly percentages use that week's starting weight
Some programs and weight loss challenges track the percentage lost each week. For that, use the weight at the start of the week as the starting weight. Losing 2 lbs in a week from 180 lbs is 1.11% for that week.
The scale measures more than fat
Body weight includes water, muscle, food and fat. Day-to-day readings can move because of water and meals alone. For a clearer picture, weigh at the same time of day under the same conditions and look at the trend over several weeks rather than any single reading.
What Percentage of My Weight Have I Lost If...
What percentage have I lost if I went from 200 to 180 lbs?
Going from 200 lbs to 180 lbs is a 10% weight loss. You lost 20 lbs, and 20 ÷ 200 × 100 = 10%. That is the second milestone in the calculator's table.
What percentage have I lost if I went from 250 to 230 lbs?
Going from 250 lbs to 230 lbs is an 8% weight loss. 20 lbs ÷ 250 lbs × 100 = 8%. The same 20 lbs is a bigger share for someone who started lighter.
What percentage have I lost if I went from 180 to 165 lbs?
Going from 180 lbs to 165 lbs is an 8.33% weight loss. You lost 15 lbs, and 15 ÷ 180 × 100 = 8.33%. You have passed the 5% milestone (171 lbs) and are 3 lbs from 10% (162 lbs).
What percentage have I lost if I went from 90 kg to 81 kg?
Going from 90 kg to 81 kg is a 10% weight loss. 9 kg ÷ 90 kg × 100 = 10%. Kilograms and pounds give the same percentage, as long as both weights use the same unit.
What percentage have I lost if I lost 10 lbs from 150 lbs?
Losing 10 lbs from 150 lbs is a 6.67% weight loss. 10 ÷ 150 × 100 = 6.67%. Your current weight is 140 lbs.
What percentage have I lost if I lost 30 lbs from 300 lbs?
Losing 30 lbs from 300 lbs is a 10% weight loss. 30 ÷ 300 × 100 = 10%. It took 30 lbs to reach 10% here, compared with 20 lbs from a 200 lb start.
What percentage have I lost if I lost 1.5 lbs a week for 12 weeks from 160 lbs?
Losing 1.5 lbs a week for 12 weeks from 160 lbs is an 11.25% weight loss. That is 18 lbs in total, and 18 ÷ 160 × 100 = 11.25%. Real progress is rarely this even from week to week, so treat steady-rate figures as an estimate.
What percentage have I lost if my weight went up?
If your weight went up, the result is negative: 200 lbs to 206 lbs shows −3%. The calculator subtracts current from starting weight, so a gain gives a negative "% lost". −3% means you have gained 3% of your starting weight.
What is 5% and 10% of my weight if I weigh 220 lbs?
At 220 lbs, 5% is 11 lbs (target 209 lbs) and 10% is 22 lbs (target 198 lbs). Multiply your weight by 0.05 or 0.10 to get the amount, then subtract it from your weight. The Find Target Weight tab does this for any percentage.
How much do I need to lose to reach 10% if I weigh 185 lbs?
At 185 lbs, a 10% loss is 18.5 lbs, which brings you to 166.5 lbs. 185 × 0.10 = 18.5, and 185 − 18.5 = 166.5.
People Also Search For
How to calculate weight loss percentage by hand
Subtract your current weight from your starting weight, divide by your starting weight, and multiply by 100. From 200 lbs to 185 lbs: 200 − 185 = 15, 15 ÷ 200 = 0.075, and 0.075 × 100 = 7.5%.
Weight loss percentage formula in Excel or Google Sheets
With the starting weight in A2 and the current weight in B2, use =(A2-B2)/A2 and format the cell as a percentage. For a weekly log, put each week's weight in a new row and keep A2 fixed as $A$2 so every row is measured from the same start.
How much is 5% of my body weight
Multiply your weight by 0.05. At 170 lbs, 5% is 8.5 lbs. At 240 lbs it is 12 lbs. At 80 kg it is 4 kg. Enter your weight and 5 on the Find Target Weight tab to get your exact target.
How to calculate weight loss percentage for a challenge
Use each person's weight at the official start weigh-in as the starting weight. Weight loss challenges usually rank by percentage so that people of different sizes compete fairly. Someone who goes from 200 lbs to 182 lbs (18 lbs, 9%) beats someone who goes from 250 lbs to 230 lbs (20 lbs, 8%), even though they lost fewer pounds.
Weight loss percentage vs body fat percentage
Weight loss percentage is the share of total body weight you have lost; body fat percentage is the share of your current body that is fat. They measure different things. Your scale weight can drop without any change in body fat (for example, water loss), and body fat can fall while your weight stays the same.
How to work out a weekly weight loss percentage
Divide the weight lost that week by your weight at the start of that week, then multiply by 100. Going from 180 lbs to 178 lbs in a week is 2 ÷ 180 × 100 = 1.11%. To see your total progress, use your original starting weight instead.
Frequently Asked Questions
What is a healthy rate of weight loss?
The CDC notes that people who lose weight gradually and steadily, about 1 to 2 pounds (roughly 0.5 to 1 kg) per week, are more likely to keep the weight off than people who lose it faster. The right pace for you depends on your health, so talk to a doctor before setting a target.
Why should I track weight loss as a percentage rather than just pounds?
Percentage of body weight lost is a fairer and more meaningful measure across different body sizes. Losing 10 lbs means very different things for someone who started at 120 lbs versus 300 lbs. Percentage accounts for your individual baseline, which is why health guidance and weight loss challenges often use it.
What is a weight loss plateau and how do I handle it?
A plateau is a period when your weight stops going down even though you have not changed your habits. It is common after a period of steady loss, partly because a smaller body uses less energy. Look at your trend over several weeks rather than a few days, and talk to a doctor or registered dietitian if you are unsure what to change.
How significant is a 5% weight loss for health?
The CDC notes that even a modest weight loss of 5 to 10 percent of total body weight is likely to produce health benefits, such as improvements in blood pressure, blood cholesterol and blood sugar. For a 200 lb person, 5% is 10 lbs. Your doctor can tell you what a meaningful target is for you.
What if my current weight is higher than my starting weight?
If your current weight exceeds your starting weight, the calculator shows a negative percentage, indicating weight gain rather than loss. This is mathematically correct — a negative "% lost" means you have gained that percentage of your original weight. For example, 200 lbs to 206 lbs shows −3%.
Does it matter if I use pounds or kilograms?
No. The percentage is the same in either unit, as long as both weights use the same one. 200 lbs to 180 lbs and 90.72 kg to 81.65 kg are both a 10% loss. Do not mix units, such as a starting weight in kg and a current weight in lbs.
How does the Find Target Weight tab work?
It multiplies your starting weight by (1 − target% ÷ 100). For a 10% goal from 200 lbs, that is 200 × 0.90 = 180 lbs, and the weight to lose is 20 lbs. It is a quick way to turn a percentage goal into a number on the scale.
Which starting weight should I use?
Use the weight you recorded when you began the plan you are tracking. If you restart after a break, you can either keep your original start to see total progress or use a new start to track the new phase. Just be consistent, because the percentage depends entirely on the starting weight.
Does the percentage show how much fat I have lost?
No. It shows the change in total body weight, which includes fat, muscle, water and the contents of your digestive system. Body fat has to be measured separately, for example with a body composition scale or other methods a health professional can advise on.
Is this calculator medical advice?
No. It does the arithmetic only and does not know your health history. Talk to a doctor before starting a weight loss plan, and see one promptly if you are losing weight without trying.
Is my data stored or sent anywhere?
No. All calculations run in your browser. Nothing you type is sent to a server or saved, and no account is needed.
Last reviewed: November 2026 — formulas and worked examples verified.