Calories to lose weight: a moderate deficit.

A moderate calorie deficit means eating 10% to 20% below daily burn (TDEE). A 30-year-old man who is 5 ft 11 in and weighs 180 lb, moderately active, burns about 2,788 calories. At a 15% deficit, the target is 2,370 calories, 418 fewer a day. Without medical supervision, women should not go below 1,200 calories and men not below 1,500.

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Target with a moderate deficit

Daily burn (Mifflin-St Jeor × activity) minus the deficit you pick.

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Daily targetcalterix
2,370 calories
418 calories a day below a burn of 2,788 calories. In theory, about 0.8 lb per week.
  • Estimated daily burn2,788 calories
  • Deficit applied418 calories (15%)
  • Safety floor1,500 calories
  • Daily target2,370 calories
A reference calculation for healthy adults. Not a diet or a promise of results. Talk with a doctor or registered dietitian.

How the deficit is calculated

The starting point is total daily energy expenditure (TDEE): Mifflin-St Jeor BMR times an activity factor, as in the calorie calculator. The deficit is a percentage of daily burn, capped at 20%. BMR is the base of the math, and daily burn is the result after the activity factor.

Target = daily burn × (1 − deficit)
Pace (lb per week) = daily deficit × 7 ÷ 3,500
Example: daily burn of 2,788 and a 15% deficit. Target = 2,788 × 0.85 = 2,370 calories. Daily gap = 418, about 0.8 lb per week.
DeficitTarget for a burn of 2,400Gap per day
10%2.160 calories240 calories
15%2.040 calories360 calories
20%1.920 calories480 calories
Sample numbers for a daily burn of 2,400 calories.

Safety limits

  • Floor of 1,200 calories for women and 1,500 for men. Going below needs a doctor or registered dietitian. The calculator never suggests a target below the floor.
  • Losing weight too fast raises the risk of muscle loss, gallstones, and low nutrient intake.
  • Skip this tool during pregnancy or nursing, under age 18, with a history of eating disorders, or with conditions like diabetes, unless a professional guides you.

Before picking a goal weight, check your BMI and the ideal weight range for your height. Resting burn is explained in the BMR calculator.

The 3,500 calorie rule

The rule says a pound of body fat holds about 3,500 calories, so a 500 calorie daily deficit means roughly a pound a week. The math gives a ballpark but overstates real loss: metabolism slows as weight drops, some lost weight is water and lean mass, and people slip.

That is why the pace and timeline tab shows a theoretical timeline. Real progress tends to be slower and uneven. Judge it by multi-week trends, not by single days.

This page does not prescribe a diet or promise weight loss. The result is a reference calculation.

Back to the calculator

Main calculatorCalorie calculatorDaily calories burned and calories per workout

Frequently asked questions

How many calories should I eat a day to lose weight?

Typically 10% to 20% below daily burn, with a floor of 1,200 calories for women and 1,500 for men. At a burn of 2,788 calories, a 15% deficit is 2,370 calories.

What is a safe calorie deficit?

A moderate deficit, 10% to 20% of daily burn or about 250 to 750 calories a day, is usually well tolerated by healthy adults. Larger deficits call for professional supervision.

How do I figure out my calorie deficit?

Estimate daily burn (BMR times an activity factor), then subtract the deficit percentage. With a burn of 2,788 and a 15% deficit, the target is 2,788 × 0.85 = 2,370 calories.

How much weight can I lose in a week?

By the 3,500 calorie rule, a 500 calorie daily deficit works out to about 1 lb a week. Real results vary, and losing more than 1% of body weight a week needs medical oversight.

Is it OK to eat less than 1,200 calories a day?

Only with a doctor or registered dietitian watching. Very low calorie diets without supervision raise the risk of nutrient gaps and muscle loss.

Does this calculator count calories in food or plan a diet?

No. The tool sets a daily energy target for reference, not a menu. Food calories are on the Nutrition Facts label, and a registered dietitian can build a plan around your needs.

Sources and review

  • Mifflin MD, St Jeor ST et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990.
  • U.S. Department of Agriculture and U.S. Department of Health and Human Services: Dietary Guidelines for Americans.
  • Centers for Disease Control and Prevention (CDC): Adult BMI categories.
  • Wishnofsky M. Caloric equivalents of gained or lost weight. American Journal of Clinical Nutrition, 1958.
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