Download
Calculator

Calorie Deficit Calculator

Choose a pace, and the calculator will show how many calories to eat per day, how many kilograms you could lose in a week, and roughly when you might reach your goal weight.

Sex
Weight loss rate

Enter your details and your results will appear here.

How does the calorie deficit calculator work?

First, the calculator estimates your TDEE—the calories you need to maintain your weight—using the Mifflin-St Jeor equation and your activity factor. Then it subtracts your chosen deficit and shows:

  • how many calories to eat per day to lose weight,
  • the rate of weight loss you can expect per week and month,
  • roughly when you might reach your goal weight, if you enter one.

We estimate your rate of weight loss based on the assumption that 1 kg of body fat equals about 7700 kcal. It’s a simplification, but it gives you a good sense of the scale.

What calorie deficit should you choose?

Rate Daily deficit Weight loss per week Weight loss per month
Gradual 300 kcal about 0.3 kg about 1.2 kg
Standard 500 kcal about 0.45 kg about 2 kg
Faster 750 kcal about 0.7 kg about 3 kg

For most people, 300-500 kcal works best: you can see results without hunger and low energy taking over. 750 kcal is the upper limit and is generally only appropriate for people with significant excess weight. Read more in our guide to calorie deficits.

Safe limits

  • Without professional guidance, don’t go below about 1200 kcal (women) or 1500 kcal (men). The calculator will warn you if your chosen deficit would take you below these levels.
  • Don’t aim to lose more than about 1 kg per week—losing weight faster can make it easy to lose muscle and regain the weight.
  • Your goal weight should fall within the healthy BMI range. Check it with our BMI calculator.

Why is your goal date only an estimate?

The calculator assumes a constant deficit, but in reality:

  • your weight drops faster in the first week as you lose water and glycogen,
  • your rate of weight loss slows down because the less you weigh, the fewer calories you burn,
  • your weight can fluctuate by 1-2 kg from day to day, so focus on your weekly average.

That’s why you should recalculate your goal every few kilograms—just come back here and enter your current weight. We explain how to check whether your goal is right for you in our guide to setting a calorie goal.

What should you eat in a calorie deficit?

A calorie deficit is easier to maintain when your meals are filling. It helps to include protein in every meal (find out how much you need with our protein calculator), eat plenty of vegetables, and cut back on liquid calories. Once you know your goal, break it down into macronutrients.

The hardest part of a calorie deficit is keeping track of the numbers day after day. With EatSee, you can log a meal with a photo or a short sentence, and the app will show how many calories you have left for the day.

FAQs

How many calories should I eat to lose weight?
Usually 300-500 kcal below your TDEE. For example, with a TDEE of 2300 kcal, that’s about 1800-2000 kcal per day, leading to a loss of about 0.3-0.5 kg per week.
How much weight can you lose in a month with a calorie deficit?
A daily deficit of 500 kcal amounts to about 2 kg of body fat in a month, while a deficit of 300 kcal amounts to about 1.2 kg. Your weight may drop more in the first month because you’ll also lose water.
Is a 1000 kcal deficit a good idea?
For most people, that’s too much. It’s hard to maintain and can make it easy to lose muscle. A larger deficit may be used for significant excess weight, but a doctor or dietitian should recommend it.
Why am I in a calorie deficit but not losing weight?
Most often, the deficit is smaller than it seems because of oil, drinks, snacking, and weekends. Water retention can also cause your weight to stall temporarily. Log absolutely everything for two weeks, and if nothing changes, lower your goal by 100-150 kcal.
Does the calculator account for exercise?
Yes, through the activity factor. Choose the level that reflects your entire week, and don’t add calories from your watch separately, or you’ll count the same activity twice.

This calculator is for informational purposes only and does not replace advice from a doctor or dietitian. The calculations happen in your browser—we don’t send the data you enter anywhere. We only save it in this tab for the duration of your visit, so it can be filled in automatically in other calculators. Formulas and sources.

Other calculators