Weight Loss Calculator: How Long to Reach Your Goal Weight

Find out how long it will take to reach your goal weight and what date you could get there. Choose a weekly loss rate and the calculator shows the number of weeks, the target date, the daily calorie deficit required and a week-by-week weight table. Example: going from 200 lb to 180 lb at 0.75% of body weight per week takes about 14 weeks and needs a deficit of roughly 700 calories a day.

How to use the Weight Loss Calculator

1. Choose pounds or kilograms.
2. Enter your current weight and your goal weight.
3. Pick a weekly loss rate. Slower rates are easier to sustain.
4. Press Calculate to see how many weeks it takes, your estimated goal date and a week-by-week table.

Formula and method

Weight after each week = Previous weight × (1 − rate). The number of weeks to reach the goal is the first week when the weight is at or below your goal.

The daily deficit equals the average weekly loss × 3,500 kcal per lb (7,700 per kg) ÷ 7. Example: 200 lb to 180 lb at 0.75% per week is 14 weeks and about 1.43 lb per week, which is a deficit of about 714 kcal per day.

Frequently asked questions

How fast can I safely lose weight?

Health agencies generally suggest about 1 to 2 lb (0.5 to 1 kg) per week, or 0.5% to 1% of body weight. Faster loss risks muscle loss and nutrient shortfalls.

Why does weight loss slow down?

As you lose weight your body burns fewer calories, and the same deficit produces a smaller loss. The calculator reflects this by using a percentage of your current weight each week.

Does this tell me what to eat?

No. Use the calorie deficit and TDEE calculators to set a calorie target, and check with a doctor or registered dietitian for personal advice.

Sources

• CDC: Losing weight
• NIH: Body Weight Planner

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