Calorie Calculator

Estimate how many calories a day you need to keep your weight steady, and how many to lose or gain gradually. Targets that would fall below commonly cited safe minimums are flagged instead of shown.

The equations were built from data on biological sex.

For adults 18 and over.

Most people overestimate this. If unsure, pick the lower level.

The CDC describes 1 to 2 lb a week as a gradual, steady pace for weight loss.

Calories to lose 1 lb (0.45 kg) per week
1,455
per day (−500 from maintenance)
Maintenance calories (TDEE)
1,955
BMR (Mifflin-St Jeor)
1,422
Safe minimum used for weight loss
1,200women
  • Uses the rule of thumb that a pound of body weight is about 3,500 calories (500 a day for 1 lb a week). Real loss usually slows over time as your body adapts, so recheck every few weeks.
  • Estimates for healthy adults, for information only, not medical advice. Don't use this during pregnancy or breastfeeding, if you have or have had an eating disorder, or if you have a medical condition affected by diet, without professional advice.

Daily calories for each goal

GoalCalories per dayChange from maintenance
Maintain weight1,9550
Lose 0.5 lb (0.23 kg) per week1,705−250
Lose 1 lb (0.45 kg) per week1,455−500
Lose 1.5 lb (0.68 kg) per week1,205−750
Lose 2 lb (0.91 kg) per weekBelow 1,200 minimum−1,000
Gain 0.5 lb (0.23 kg) per week2,205+250
Gain 1 lb (0.45 kg) per week2,455+500
Gain 1.5 lb (0.68 kg) per week2,705+750
Gain 2 lb (0.91 kg) per week2,955+1,000

How the numbers are worked out

First, the calculator estimates your basal metabolic rate with the Mifflin-St Jeor equation and multiplies it by an activity factor to get total daily energy expenditure (TDEE), your maintenance calories. Then it subtracts or adds calories for the rate of change you pick, using the familiar rule that a pound of body weight equals about 3,500 calories. Losing 1 lb a week means a deficit of 3,500 ÷ 7 = 500 calories a day.

Every step is an estimate. The BMR equation can be off by 10% for an individual, and activity levels are easy to overstate. Treat the result as a starting point and adjust it based on what your weight actually does.

Safe minimums, and why some numbers aren't shown

This calculator won't display a weight-loss target below 1,200 calories a day for women or 1,500 for men. These are the lower ends of the 1,200 to 1,500 (women) and 1,500 to 1,800 (men) calories-a-day diets that the 2013 AHA/ACC/TOS obesity guideline describes for weight loss. The same guideline says very-low-calorie diets, under 800 calories a day, should be used only in limited circumstances with medical supervision.

Smaller, older and less active people have lower maintenance needs, so faster rates can push them under these minimums. When that happens you'll see a caution and the fastest rate that stays above the floor. Slower loss is not a failure: the CDC notes that people who lose about 1 to 2 lb a week are more likely to keep the weight off.

Why weight loss slows down

The 3,500-calorie rule works reasonably over the first weeks but overstates long-term results. As you lose weight you burn less: a smaller body needs less energy, and metabolism adapts. NIH researchers who modeled this found the body's response to a lasting change in intake is slow, with a half time of about a year.

In practice, recalculate every 10 lb or so, or when progress stalls for several weeks. The NIH Body Weight Planner uses a dynamic model of these changes if you want a projection over time rather than a single daily number.

The calorie formula

Maintenance (TDEE) = BMR × activity multiplierTarget = TDEE − (rate in lb per week × 3,500 ÷ 7) to lose, or + to gainWeight-loss targets below 1,200 (women) or 1,500 (men) are not shown
  • BMR from Mifflin-St Jeor: 10 × kg + 6.25 × cm − 5 × age + 5 (men) or − 161 (women)
  • Activity multiplier from 1.2 (sedentary) to 1.9 (extremely active)

Example

  1. A 35-year-old woman, 5 ft 5 in and 160 lb, lightly active (multiplier 1.375).
  2. BMR = 1,422 calories a day, so maintenance = 1,421.6 × 1.375 = 1,955 calories a day.
  3. To lose 1 lb a week: 1,955 − 500 = 1,455 calories a day.
  4. To lose 1.5 lb a week: 1,954.7 − 750 = 1,205 calories a day, just above the 1,200 minimum.
  5. To lose 2 lb a week would take about 955 calories a day, which is below the minimum, so the calculator shows a caution instead and points to 1.5 lb a week.

Frequently asked questions

How many calories should I eat to lose weight?

A common starting point is about 500 calories a day below your maintenance needs, which works out to roughly 1 lb a week at first. This calculator won't show targets under 1,200 calories a day for women or 1,500 for men.

Is it safe to eat 1,200 calories a day?

1,200 is at the bottom of the range the AHA/ACC/TOS guideline describes for women's weight-loss diets. Whether it suits you depends on your size, activity and health, so it's worth checking with a doctor or dietitian.

How fast can I safely lose weight?

The CDC describes about 1 to 2 lb a week as a gradual, steady pace and says people who lose weight that way are more likely to keep it off.

Why did my weight loss stop when I'm still eating the same?

As you get lighter your maintenance calories fall, so the same intake becomes a smaller deficit. Recalculate with your new weight, and check that portion sizes haven't crept up.

How many calories to maintain weight at 5 ft 5 in and 160 lb?

For a lightly active 35-year-old woman, about 1,955 calories a day. Losing 1 lb a week would mean about 1,455.

Sources

Last reviewed for 2026. How we calculate.