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Calorie Deficit Calculator: Time to Reach Your Goal Weight

This free calorie deficit calculator estimates how long it takes to lose weight at a daily calorie deficit. Enter your current weight, goal weight and deficit to see weekly loss and a date.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

Weight loss comes from using more energy than you eat. A calorie deficit is the daily gap. If you know the gap and the weight you want to lose, you can estimate the time it takes.

Enter your current weight, your goal weight and your daily deficit to see the weeks needed and the expected date.

How to Use This Tool

  1. Enter your current weight.
  2. Enter your goal weight.
  3. Enter your daily calorie deficit.
  4. Press Calculate.

How the Calculation Works

Weight to lose = current − goal. One kilogram of fat is about 7,700 calories, so weekly loss = deficit × 7 ÷ 7,700. Weeks needed = weight to lose ÷ weekly loss. The model is simple and ignores the drop in energy needs as you lose weight, so real progress is a little slower near the end.

Worked Example

Losing 8 kg (80 to 72) with a 500 calorie daily deficit means about 0.45 kg a week and about 18 weeks. The total deficit needed is about 61,600 calories.

Common Uses

  • Setting realistic goals.
  • Planning a diet.
  • Understanding why loss is slow.
  • Tracking progress.

Tips and Common Mistakes

  • Aim for a loss of 0.25 to 1 kg a week.
  • Update your numbers every few weeks.
  • Pair with strength training to protect muscle.

Next, you may need the BMR and TDEE calculator, BMI calculator, ideal weight calculator, body fat calculator.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

About 1 kilogram of body fat holds roughly 7,700 calories. A daily deficit of 500 calories gives about 0.45 kg a week.
Not usually. Large deficits can cost muscle and energy. A common safe range is 0.25 to 1 kg a week.
As you lose weight, your body needs fewer calories, so the same deficit gives less loss. Recalculate as your weight changes.
No. It is a simple model. Speak to a doctor before starting a diet, especially if you have health conditions.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.