How many calories should I eat a day?

The short answer

Most adults land somewhere between 1,600 and 3,000 calories a day. Where you fall depends on four things: how big you are, how much you move, how old you are, and whether you are trying to lose, hold or gain weight. The estimate below is the same calculation clinicians and sports dietitians start from.

Step	What it gives you
1. Resting metabolic rate	Calories your body uses at complete rest
2. Activity multiplier	Your total daily burn, including movement and exercise
3. Goal adjustment	The target you actually eat to

Run the calculation for your own numbers →

Step one: resting metabolic rate

The Mifflin-St Jeor equation is the one most often recommended for healthy adults, because it predicted measured resting energy expenditure more accurately than the older Harris-Benedict equations in the review that established current practice.^[1]

Sex	Equation
Male	(10 × kg) + (6.25 × cm) − (5 × age) + 5
Female	(10 × kg) + (6.25 × cm) − (5 × age) − 161

A 30-year-old woman at 68 kg and 165 cm: (10 × 68) + (6.25 × 165) − (5 × 30) − 161 = 1,400 calories at rest.

The sex term is in the equation because it estimates lean mass, which is what actually burns the energy. It is a statistical adjustment, not a statement about anyone.

Step two: how much you move

Multiply the resting figure by an activity factor. Most people overestimate this, which is the single largest source of error in the whole calculation.

Activity	Multiplier	Our example
Desk job, little exercise	1.2	1,680
Light exercise, 1–3 days a week	1.375	1,925
Moderate exercise, 3–5 days	1.55	2,170
Hard exercise, 6–7 days	1.725	2,415

If you sit for work and train three times a week, you are usually closer to 1.375 than 1.55. An hour in the gym is a small share of a day that is otherwise spent sitting.

Step three: adjust for the goal

Goal	Adjustment	Our example at 1.375
Lose fat	−15 to −20%	1,540–1,635
Maintain	No change	1,925
Gain muscle	+10 to +15%	2,120–2,215

Deficits larger than about 20 per cent tend to cost lean mass and get harder to stick to, which is why the range stops there rather than going lower.

Why the number is an estimate, and what to do about it

Prediction equations carry real error for any one person: measured resting energy expenditure commonly sits within about 10 per cent of the predicted value, and sometimes further out.^[1] On a 2,000-calorie target that is a 200-calorie band before you have eaten anything.

So treat the output as a starting point and correct it from evidence:

• Eat to the estimate for two full weeks, weekends included.
• Weigh yourself under the same conditions and use the weekly average, not any single morning.
• If the average has not moved in the direction you want, change the target by roughly 100–150 calories and repeat.

Two weeks is the shortest window that outlasts the water-weight noise from salt, carbohydrate and menstrual-cycle changes. Anything faster is reading the scale, not your metabolism.

Turning the target into meals

A daily number only helps if you can spend it. Once you have your target, the harder question is what a given restaurant order costs against it — which is what the finder is for: it ranks real menu items against a goal and shows calories, protein, fiber and sodium together.

Find meals that fit your target →

Educational information, not individualized medical advice. If you are pregnant, managing a health condition, or working with a clinician on your intake, follow their guidance over a general equation.