How Many Calories Should I Eat to Lose Weight?

What is the calorie deficit formula?

The calorie deficit formula is: daily calorie target = maintenance calories − (weekly weight loss × 3,500 ÷ 7). Maintenance calories are your total daily energy expenditure (TDEE), the calories you burn in a typical day. The 3,500 figure is the common rule of thumb for the calories in a pound of body weight, about 7,700 per kilogram.

That gives three standard deficits. Losing 0.5 pound a week takes 250 calories a day, 1 pound takes 500, and 2 pounds takes 1,000. In metric units, our calorie calculator uses 275, 550 and 1,100 calories a day for 0.25, 0.5 and 1 kg a week.

How do you calculate calorie intake for weight loss, step by step?

Calculate your basal metabolic rate, multiply it by your activity level to get maintenance, then subtract a deficit and check the result against safe minimums.

• Estimate your BMR (basal metabolic rate), the calories you burn at complete rest. Our calculators use the Mifflin-St Jeor equation: 10 × weight in kg + 6.25 × height in cm − 5 × age, then + 5 for men or − 161 for women.
• Multiply BMR by an activity factor: 1.2 for sedentary, 1.375 for light exercise 1 to 3 times a week, 1.465 for moderate exercise 4 to 5 times a week, and up to 1.9 for very intense daily exercise or a physical job. The result is your TDEE.
• Subtract 250, 500 or 1,000 calories for 0.5, 1 or 2 pounds a week.
• Check the result. If it is below 1,200 calories a day for a woman or 1,500 for a man, choose a slower rate.
• Weigh yourself regularly for two to four weeks and adjust by 100 to 200 calories if the trend is faster or slower than planned.

What does the calculation look like with real numbers?

Example one: a 35-year-old woman, 5 feet 5 inches (165.1 cm) and 160 pounds (72.6 kg), who exercises 1 to 3 times a week. Her Mifflin-St Jeor BMR is 1,422 calories. Multiplied by 1.375 for light activity, her TDEE is 1,955 calories. Subtracting 500 gives a target of 1,455 calories a day for about 1 pound a week.

Example two: a 40-year-old man, 5 feet 10 inches (177.8 cm) and 200 pounds (90.7 kg), with the same activity level. His BMR is 1,823 calories, his TDEE is 2,507, and his target for 1 pound a week is 2,007 calories.

The table shows each goal for both people, as our calculator reports it. Notice that the 2-pound-a-week row takes the woman to 955 calories, well under the 1,200 minimum, so that rate is not appropriate for her without medical supervision. For the man, 2 pounds a week lands at 1,507, right at the edge of the 1,500 floor.

How fast is it safe to lose weight?

A safe and sustainable rate for most adults is about 1 to 2 pounds (0.5 to 1 kg) a week. The CDC notes that people who lose weight gradually and steadily are more successful at keeping it off.

Rate can also be judged against body size. Our calorie deficit calculator flags plans that exceed about 1% of body weight a week, because faster loss raises the risk of muscle loss and gallstones. For the 160-pound woman, 1 pound a week is 0.63% of her body weight, and reaching a goal of 140 pounds takes about 20 weeks at a 500-calorie daily deficit.

A smaller deficit is often easier to keep. If 500 calories a day leaves you very hungry or tired, 250 calories a day still produces steady loss of about half a pound a week.

Why does weight loss slow down over time?

Weight loss slows because a smaller body burns fewer calories, so the same intake produces a smaller deficit over time. The body also adapts to eating less in ways the 3,500-calorie rule does not capture.

Our calorie deficit calculator shows the first effect in its weekly plan. For the 160-pound woman, maintenance falls from 1,955 calories in week 1 to 1,911 calories by week 8, when she weighs about 153 pounds, so her target drops from 1,455 to 1,411 to keep the same 500-calorie deficit.

Research led by Kevin Hall at the National Institutes of Health found that the 3,500-calorie rule overestimates long-term weight loss because it ignores these changes. The NIDDK Body Weight Planner, built on that research, models them, and is useful for long plans. A practical habit is to recalculate your targets after every 10 pounds or so.

Which calculator should you use: calorie, calorie deficit or TDEE?

Use the calorie calculator for targets at standard rates, the calorie deficit calculator when you have a goal weight or date, and the TDEE calculator when you only need maintenance.

The calorie calculator lists maintenance and the targets for losing or gaining 0.5, 1 and 2 pounds a week. The calorie deficit calculator takes a goal weight plus either a weekly rate or a target date, then works out the daily deficit, the time to goal and a week-by-week plan. The TDEE calculator shows maintenance at every activity level, which helps if your activity changes during the week. For more on how BMR and TDEE differ, see TDEE vs BMR.

What should those calories be made of?

Within your calorie target, prioritize protein, fiber-rich foods and enough fat to stay full, and include strength training to keep muscle. Protein of about 1.2 to 1.6 g per kilogram of body weight, the range in the 2025–2030 Dietary Guidelines for Americans, is a sensible target during weight loss; see how much protein you need.

To turn a calorie target into grams of protein, carbohydrate and fat, read how to calculate macros. Drinks count too: replacing sugary drinks with water is one of the simplest ways to cut calories without eating less food, as covered in how much water to drink.

When should you get medical advice before cutting calories?

Talk to a doctor or registered dietitian before starting a calorie deficit if you are pregnant or breastfeeding, under 18, have a current or past eating disorder, have kidney disease, or take medication for diabetes or blood pressure. Calorie needs and safe rates of loss differ in each of these situations.

Also check with a clinician if your goal weight would put you below a BMI of 18.5, the lower limit of the healthy range for adults. Our guide on what a healthy BMI is shows that range for your height.