How Many Calories Should I Eat?

How many calories do you need?

The honest answer is "it depends", but it depends on things you can measure. Your age, sex, height, weight and how active you are explain most of the difference between a person who maintains on 1,700 calories and one who maintains on 3,000. Enter yours above and the calculator shows your maintenance calories, plus targets for gentle loss, steady loss, faster loss and gain, side by side.

Average daily calories by age and activity

These are maintenance calories for a woman who is 5'4" and 150 lb and a man who is 5'9" and 180 lb, using the same formula as the calculator. Use them as a rough guide, then run the calculator for your own numbers.

Two patterns stand out. Needs drop by roughly 50 to 60 calories a day per decade as metabolism slows, and moving from sedentary to moderately active is worth around 500 calories a day, more than any age effect.

Calories to lose, maintain or gain

• To lose weight, eat 250 to 500 calories below maintenance for a steady 0.5 to 1 lb a week. Go bigger only if you have a lot to lose. The calorie deficit calculator shows how long it will take.
• To maintain, eat at your maintenance number and adjust by 100 to 200 calories if your weight drifts over a few weeks.
• To build muscle, eat 250 to 500 calories above maintenance alongside strength training. The smaller surplus keeps fat gain down.

How the calculation works

The calculator uses the Mifflin-St Jeor equation, which a review by the Academy of Nutrition and Dietetics found to be the most accurate of the common formulas for healthy adults. It estimates the calories you burn at complete rest (BMR) and multiplies that by an activity factor between 1.2 and 1.9 to get your total daily energy expenditure (TDEE).

No formula knows your body exactly, so treat the result as a starting point. Eat at your target for two to three weeks, track your weight trend, and nudge the number up or down. That feedback loop is far more accurate than any equation.

Protein matters as much as calories

The calculator also suggests a protein range of 1.6 to 2.2 g per kg of body weight. Eating enough protein helps you keep muscle while losing fat and keeps you fuller on fewer calories. Our protein calculator goes into more detail.

Knowing your number only helps if you can see how close you are to it. Bento Bunny shows your remaining calories for the day and logs meals from a photo or a quick sentence, so checking in takes seconds.