How many calories should I eat a day?

Most adult women need roughly 1,600 to 2,400 calories a day and most adult men roughly 2,000 to 3,000, depending on age and how active they are. Your own number can be estimated more closely from your height, weight and activity.

By the Calcist team · Updated October 26, 2026 · About a 4-minute read

Calorie needs by age and activity

{_tbl(["Group", "Sedentary", "Active"], [ ["Men, 19–60", "2,200–2,600", "2,600–3,000"], ["Women, 19–60", "1,600–2,000", "2,200–2,400"], ["Men, 61 and over", "2,000", "2,400–2,600"], ["Women, 61 and over", "1,600", "2,000"], ["Boys, 7–18", "1,400–2,400", "1,800–3,200"], ["Girls, 7–18", "1,200–1,800", "1,800–2,400"]])}

From the Dietary Guidelines for Americans, 2020–2025, as summarized by the Merck Manual. Calorie needs rise until about age 20, then slowly fall, and rise with activity.

Find your own maintenance calories

"Maintenance calories" is what keeps your weight steady. It's estimated in two steps:

BMR, the energy your body uses at rest, from the Mifflin–St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, or − 161 for women.
Multiply by an activity factor, from about 1.2 for desk-bound days to about 1.9 for hard physical work or training. That gives your total daily energy expenditure (TDEE).

The TDEE calculator does both steps, and the calorie calculator adjusts the result for a weight goal. Treat it as a starting estimate and adjust after a few weeks of tracking your weight.

Calories in protein, carbs, fat and alcohol

{_tbl(["Nutrient", "Calories per gram"], [["Protein", "4"], ["Carbohydrate", "4"], ["Fat", "9"], ["Alcohol", "7"]])}

These are the general Atwater factors used for food labels. A meal with 30 g protein, 50 g carbs and 15 g fat has about 30 × 4 + 50 × 4 + 15 × 9 = 455 calories. Split your calories into grams with the macro calculator.

Limitations

These are population estimates. Your real needs can differ by several hundred calories because of body composition, genetics, health conditions, medications, pregnancy or breastfeeding. A doctor or registered dietitian can help if you have a medical condition or a large amount of weight to change.

Sources: Merck Manual: estimated calories needed (from the Dietary Guidelines for Americans 2020–2025); University of Minnesota Nutrition Coordinating Center: Atwater factors.

Every worked example on this page was checked with Calcist's own engine and an independent reference.

Questions people ask

How many calories should I eat a day?

Most adult women need about 1,600 to 2,400 and most adult men about 2,000 to 3,000 calories a day, depending on age and activity. Estimate your own with the TDEE calculator.

How do I figure out my maintenance calories?

Estimate your BMR from height, weight, age and sex, then multiply by an activity factor (about 1.2 to 1.9). Check it by tracking your weight for a few weeks.

How many calories are in a gram of protein?

4 calories, the same as carbohydrate. Fat has 9 calories per gram and alcohol 7.

Is 1,400 calories a day enough?

It's below the Dietary Guidelines' estimates for nearly all adults. Some people use a lower intake for weight loss for a while, but it's worth discussing with a doctor or dietitian.