How to Calculate Weight Loss Percentage

To calculate your weight loss percentage, subtract your current weight from your starting weight, divide the result by your starting weight, and multiply by 100. If you started at 95 kg and now weigh 85 kg, you have lost 10.5% of your starting weight.

This guide is general information, not medical advice. Weight loss percentage is one way to track progress, outcomes vary between individuals, and a GP or accredited practising dietitian can help you set goals that suit your health.

On this page

1. Weight loss percentage calculator
2. Key Points
3. The Weight Loss Percentage Formula
4. Why Use a Percentage Instead of Kilograms?
5. Weight Loss Percentage Table: 5% and 10% Goals
6. What Is a Healthy Pace?
7. Tracking Your Percentage Over Time
8. What Weight Loss Percentage Does Not Show
9. Other Ways to Measure Progress
10. When to Speak With a Healthcare Professional
11. Frequently Asked Questions

Got your numbers? If you want a doctor to look at your weight plan as a whole, check whether you are eligible for a medical weight loss plan. Online, no appointment needed.

Key Points

• Weight loss percentage = (starting weight minus current weight) ÷ starting weight × 100.

• A percentage lets you compare progress fairly, whatever your starting weight.

• Losing even 5 to 10% of your body weight can have significant health benefits and reduce the risk of complications (healthdirect).

• A gradual pace is around 1 to 4 kg a month to begin with. Rates vary between individuals.

• Weight loss percentage does not show fat versus muscle, water changes or health gains, so track your waist and your health too.

The Weight Loss Percentage Formula

Weight loss percentage = (starting weight minus current weight) ÷ starting weight × 100

Step by step:

1. Subtract your current weight from your starting weight. This is the weight you have lost.

2. Divide that number by your starting weight.

3. Multiply by 100 to turn it into a percentage.

Worked example. You started at 95 kg and now weigh 85 kg.

• 95 minus 85 = 10 kg lost

• 10 ÷ 95 = 0.105

• 0.105 × 100 = 10.5%

You have lost 10.5% of your starting body weight. The formula works the same way in pounds, as long as you use the same unit for both weights.

Working out how many kilograms a percentage is

To turn a percentage goal into kilograms, multiply your starting weight by the percentage and divide by 100. For a 5% goal from 90 kg: 90 × 5 ÷ 100 = 4.5 kg.

Why Use a Percentage Instead of Kilograms?

Losing 10 kg means something very different at a starting weight of 60 kg than at 120 kg. A percentage puts progress on the same scale for everyone. The table shows the same 10 kg loss from three starting weights. It is arithmetic only, not a prediction.

Percentages also match how health professionals set goals. Losing even 5 to 10% of your body weight can have significant health benefits and reduce the risk of complications (healthdirect). A good weight management service may aim for 10 to 20% of total body weight in the longer term, if required (Better Health Channel).

Weight Loss Percentage Table: 5% and 10% Goals

Use the table to see what the common 5% and 10% goals mean in kilograms. Find the row closest to your starting weight. These are arithmetic illustrations, not targets or expected results, and outcomes vary between individuals.

Smaller amounts still count. Even small amounts of weight loss, as little as 5%, can bring health benefits, including a lower risk of heart disease or type 2 diabetes (healthdirect).

What Is a Healthy Pace?

A gradual weight loss of around 1 to 4 kg a month to begin with is what a good weight management service will recommend (Better Health Channel). For someone starting at 100 kg, that is about 1 to 4% of starting weight a month. For a lighter starting weight, the same kilograms are a larger percentage. The pace tends to slow after the first stages, and rates vary between individuals. For the weekly and monthly detail, see how much weight you can realistically lose in a month.

The pace comes from the everyday basics: a healthy diet with a moderate energy gap (the Australian Obesity Management Algorithm, 2024, puts a modest deficit at about 2,000 to 4,000 kJ, or about 480 to 960 calories, a day) and regular physical activity. If you prefer to plan meals by protein, carbohydrate and fat, see working out your macros for weight loss. For ideas that fit into a normal week, see our guide to everyday habits that support weight loss.

Tracking Your Percentage Over Time

If you weigh yourself regularly, a few tips make the number more useful:

• use the same starting weight every time, so each result compares with the same point

• weigh yourself regularly, and work out your percentage monthly to see the trend rather than one reading

• write the results down, alongside your waist measurement

If your weight and waist have not changed after a few months of steady effort, or weight is coming back, it is a good time to review your habits and the possible causes of weight gain with a doctor or nurse practitioner.

What Weight Loss Percentage Does Not Show

The percentage is useful, but it leaves a lot out:

• Body composition. It does not separate fat from muscle. When weight comes off over too short a time, some of the loss is muscle.

• Water. Weight can change with fluid. On a low-carbohydrate diet, for example, weight lost at the beginning is mostly water, not body fat.

• Health improvements. Better sleep, more energy, and lower blood pressure, blood glucose or cholesterol do not appear in the number.

Other Ways to Measure Progress

Use weight loss percentage as one tool among several:

• waist circumference: a waist of 94 cm or more for males, or 80 cm or more for females who are not pregnant, carries a higher risk of health problems

• how your clothes fit

• energy levels, sleep and mood through the day

• strength and fitness when you are active

• blood pressure, cholesterol and blood glucose, checked by your GP

If you are working towards a larger loss over time, see our guide to looking after your skin during larger weight loss.

When to Speak With a Healthcare Professional

Talk to your GP if your weight changes without a clear reason, if there is no loss after a few months of steady effort, or if food and weight are causing you distress. A GP can check for health conditions and medicines that affect weight and refer you to a dietitian, exercise physiologist or psychologist.

For some adults living with obesity, a doctor or nurse practitioner may also discuss medical weight loss treatment, which is used together with a healthy diet and physical activity. Whether it suits you is a decision for a registered healthcare practitioner after an individual assessment. See who may be suitable for weight loss treatment and what happens at a weight loss consultation.

When your percentage has stopped moving despite real effort, Burst Health provides medical weight loss plans online after review by an Australian-registered doctor or nurse practitioner, and you can check whether you are eligible.

Frequently Asked Questions

How do you calculate weight loss percentage?

Subtract your current weight from your starting weight, divide by your starting weight, then multiply by 100. For example, from 95 kg to 85 kg is 10 kg lost, and 10 ÷ 95 × 100 is 10.5%. Always use the same starting weight and the same unit, kilograms or pounds, for both weights so your results compare over time.

How much is 5% body weight loss?

It is your starting weight multiplied by 0.05. At 80 kg, 5% is 4 kg; at 100 kg, it is 5 kg; at 120 kg, it is 6 kg. Even a 5% weight loss can bring health benefits, including a lower risk of heart disease or type 2 diabetes, and losing 5 to 10% of body weight can have significant health benefits (healthdirect). Outcomes vary between individuals.

What is a healthy weight loss percentage per week?

Australian guidance uses kilograms rather than a weekly percentage. One Better Health Channel page calls about ½ to 1 kg a week reasonable, and a separate one gives the 1 to 4 kg a month above, about 0.2 to 0.9 kg a week. At 100 kg, ½ to 1 kg is 0.5 to 1% a week. Rates vary between individuals, so a GP can help you set a pace.

Is losing 20% of your body weight a lot?

Yes. 20% is the top of the 10 to 20% longer-term range that a good weight management service may aim for, if required, and it is well above the 5 to 10% of body weight that healthdirect says can already bring significant health benefits. Larger goals like this are best set and reviewed with a GP. Outcomes vary between individuals.

References

• Markovic TP, et al. The Australian Obesity Management Algorithm (July 2024).

• healthdirect. Body mass index (BMI) and waist circumference.

• Better Health Channel (Victorian Government). Weight management services.

• Better Health Channel (Victorian Government). Weight loss: a healthy approach.

• Better Health Channel (Victorian Government). Weight loss: common myths.

• healthdirect. Obesity.

• healthdirect. Fluid retention.

This article is general information only and does not replace individual medical advice. Please speak with a registered Australian healthcare practitioner about your own circumstances.