How many calories should I eat a day is the question that opens every diet, and the short answer misleads more than it helps. "2,000 kcal" became a label number, not a recommendation for you. Your real value depends on weight, height, age, activity level, and above all what you want from your body over the next 12 weeks.
Most people guess a round number, follow it for two weeks, and quit without knowing why. The usual reason is a target set wrong. Before you cut bread or swap a meal, it is worth spending five minutes defining the number that fits your body right now.
The short answer before the long one
Without touching the formula, the average maintenance value for adults usually lands in these bands, useful as a starting reference for intake, broadly in line with the estimated calorie needs in the USDA Dietary Guidelines:
| Profile | Sedentary | Moderately active | Active |
|---|---|---|---|
| Woman 18 to 30 | 1,800 to 2,000 kcal | 2,000 to 2,200 kcal | 2,200 to 2,400 kcal |
| Woman 31 to 50 | 1,600 to 1,800 kcal | 1,800 to 2,000 kcal | 2,000 to 2,200 kcal |
| Man 18 to 30 | 2,400 to 2,600 kcal | 2,600 to 2,800 kcal | 3,000 kcal or more |
| Man 31 to 50 | 2,200 to 2,400 kcal | 2,400 to 2,600 kcal | 2,800 to 3,000 kcal |
That table is a starting point. For your exact number, it is worth running the Mifflin-St Jeor formula in the calorie calculator guide, or the broader TDEE calculator guide.
How many calories should I eat to maintain my weight
Maintaining your weight means eating the equivalent of your total daily energy expenditure (TDEE). It is the sum of four parts: basal metabolism (60% to 75% of the total), the thermic effect of food (about 10%), planned exercise (10% to 20%), and the spontaneous movement of the day, your NEAT (5% to 15%). The balance between what comes in and what the body burns is the base of weight control, a point the Harvard Nutrition Source keeps returning to.
For a 30-year-old woman, 65 kg, 1.65 m, with a sedentary routine and light training three times a week, the estimated TDEE sits around 1,900 to 2,000 kcal. Eating in that band, with small daily swings, holds the weight for months.
The critical point here is not nailing the number on any single day, it is nailing the weekly average. Nobody eats 100% of their TDEE every day. Someone who eats 1,700 one day and 2,100 the next holds the same weight as someone who eats 1,900 both days. Knowing how to calculate your basal metabolic rate is the first piece of that math.
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How many calories should I eat to lose weight
To lose weight, you need to eat less than your TDEE. The cut most guidelines recommend is 300 to 500 kcal a day below maintenance, which produces fat loss between 0.4 and 0.7 kg a week without sacrificing lean mass.
Back to the example of the 30-year-old woman with a TDEE of 1,900 kcal, the target to lose weight usually lands between 1,400 and 1,600 kcal a day. Below 1,200 kcal, the body shifts into defense mode, drops metabolism, and reactive hunger climbs. That is the point where extreme diets fail.
The mechanism shows up in detail in the calorie deficit guide. It is worth a look before you set the target, especially if you have tried crash diets before.
- Aggressive cut (up to 750 kcal below): reserved for high overweight and with professional supervision. It is not the rule for someone with 5 to 10 kg to lose.
- Moderate cut (300 to 500 kcal below): the safe band for most people. It fits the routine without wrecking energy.
- Minimal cut (200 kcal below): for someone near their goal weight who wants to drop the last kilos without living hungry.
How many calories should I eat to build muscle
To build muscle, the game flips: you need to eat above your TDEE. The recommended surplus is between 200 and 400 kcal a day over maintenance, combined with progressive strength training and protein between 1.6 and 2.2 g per kilo of body weight.
For a 25-year-old man, 75 kg, 1.80 m, training four times a week, the TDEE sits around 2,800 kcal. The gain target lands between 3,000 and 3,200 kcal. A surplus bigger than that turns into fat, not muscle.
A controlled surplus is what separates a clean gain from a dirty bulk: it prioritizes protein, keeps the excess small, and adjusts each week as the scale and the mirror respond. The macro calculator guide sets the protein, carb, and fat split that makes the surplus count.
Why your number can't stay fixed all year
The calorie target is not a tattoo. Five variables move the number and call for regular review:
- Weight change. Every 5 kg lost drops the TDEE by around 100 to 150 kcal. Whoever does not recalculate stalls on a plateau by week four.
- Routine change. Whoever traded the office for working from home cut their NEAT by up to 300 kcal a day without noticing.
- Exercise change. Moving from running to strength training does not mean burning less, it means burning differently.
- Life stage change. Adolescence, pregnancy, breastfeeding, and post-menopause call for a specific adjustment, ideally with a dietitian.
- Goal change. Whoever finished losing weight needs to leave the deficit, or starts eating up again with no clear reason.
Good practice is to review the target every 4 to 6 weeks, based on the week's average weight and your energy levels. Whoever keeps the same number for 6 months is usually off target by a long way.
The 4 mistakes that sink people who got the target right on paper
Mistake 1: rounding the number down. Calculating 2,100 and adopting 1,800 "to be safe" does not speed up loss, it only hurts adherence. The more aggressive the cut, the higher the chance of breaking before the month closes.
Mistake 2: using a generic calculator without logging the meal. Knowing the number is half the work. The other half is measuring whether you are close. Without a log, the calculation becomes a guess, and counting calories by photo removes the friction that makes most people quit.
Mistake 3: ignoring the weekend. Five days in a perfect deficit and two free days cancel the week's balance. The number that counts is the 7-day average, not the daily target.
Mistake 4: not reassessing after the first month. If the scale does not respond in 30 days, the target is probably too high for your reality. Adjusting is part of the method, not a sign of failure.
ContaCal: set the target and measure the balance each meal
ContaCal is the AI photo calorie counter that estimates calories and macros from a plate, and it calculates your daily target from weight, height, age, sex, activity level, and goal. The number appears in seconds and adjusts as your pace of loss or gain changes.
The difference is the input. Instead of typing each food, you photograph the plate. The AI recognizes it, estimates the portion, and returns the calories against the day's target. Whoever logs with the camera keeps tracking active for more weeks, simply because the friction drops. The same starting math runs through how to count calories.
