Daily Calorie Calculator — How Much to Eat

How many calories you should eat in a day is not a fixed figure — it is whatever matches what your body spends. The calculator estimates that spend from your sex, age, height, weight and activity, then shows the target for holding your weight, losing, or gaining. Inputs are metric: 150 lb is 68 kg, 5 ft 4 in is 163 cm.

How far apart real people land

The reason generic calorie targets fail is that the honest range is enormous. These are figures from the 2023 Dietary Reference Intakes equations, which the National Academies built from doubly labeled water measurements:

Person	Inactive	Active
Woman, 35, 5 ft 4 in, 150 lb	2,068 kcal	2,370 kcal
Woman, 70, 5 ft 4 in, 150 lb	1,823 kcal	2,125 kcal
Man, 35, 5 ft 10 in, 180 lb	2,682 kcal	3,085 kcal
Man, 70, 5 ft 10 in, 180 lb	2,303 kcal	2,706 kcal

Between the smallest and largest row there is more than 1,200 calories a day. Age alone moves the number by roughly 380 in these examples, activity by another 300 to 400. A magazine number that ignores all of that is not describing you.

What the calculator is actually doing

It runs Mifflin-St Jeor for your resting rate, then applies an activity multiplier. Resting rate is the floor — the energy your organs, brain and tissue turnover spend before you move at all — and for most adults it accounts for the majority of the day’s total. Movement is the part you can change, and the part people misjudge most; the activity level calculator is there for exactly that decision.

The full arithmetic, and how it compares with the official DRI equations, is laid out on the TDEE calculator.

The 1,200-calorie problem

Diet culture has settled on 1,200 calories as a default for women and something like 1,800 for men. Compare those with the table above and the mismatch is obvious: 1,200 sits hundreds of calories below the maintenance figure of even the least active adult woman in it. A deficit that deep buys fast early results and then charges for them in hunger, lost lean mass, and a plan nobody sticks with.

Start from your own expenditure and subtract from there. The calorie calculator for weight loss sizes that subtraction.

Let the scale audit the estimate

Any equation is a starting guess. Turn it into your number this way:

1. Eat close to the calculated target for three weeks, without changing anything else.
2. Weigh yourself under the same conditions — morning, before breakfast — and look at the weekly average rather than any one reading.
3. Weight steady means the estimate was right. Drifting up means your real requirement is lower; drifting down means it is higher. Adjust by 100 to 200 calories and run another three weeks.

Two rounds of that will beat any calculator, because it measures you instead of predicting you.

This content is informational and does not replace advice from a physician or registered dietitian.