How many calories should I eat a day to lose weight?

Take your maintenance calories and subtract 250–500 kcal/day, which produces roughly 0.25–0.5 kg (0.5–1 lb) of loss per week. For most adults that lands somewhere between 1,500 and 2,200 kcal. The right number depends on your size and activity, not on a universal figure — the calculator above works it out from your own numbers.

Is 1,200 calories a day too low?

For most adults, yes. 1,200 kcal is widely treated as the absolute floor for women and 1,500 for men, and even at the floor it is hard to hit protein and micronutrient targets. If your calculated target falls below those numbers, the fix is a slower rate of loss or more daily activity, not a smaller plate.

How many calories do I need to gain muscle?

A surplus of 150–350 kcal/day above maintenance, which supports roughly 0.25–0.5 kg per week of gain. Beyond that, the extra mostly arrives as fat, because muscle protein synthesis has a ceiling that food cannot raise. Pair the surplus with 1.6–2.2 g of protein per kg of body weight and progressive resistance training.

Is 3,500 calories really one pound of fat?

It is a useful approximation, not a law. The figure comes from pure adipose tissue being roughly 87% fat at about 9 kcal/g, but real weight change includes water, glycogen and lean tissue, and the ratio shifts as you get leaner. In practice early loss overshoots the prediction because of water, and later loss undershoots it because your burn has fallen.

Why has my weight loss stopped at the same calories?

Two reasons, both arithmetic. A lighter body burns fewer calories, so a fixed intake becomes a smaller deficit every week — the projection chart above shows the bend. On top of that, non-exercise movement quietly drops in a deficit and portion accuracy drifts over months. Recalculate at your current weight every 4–6 weeks and re-audit your logging before assuming your metabolism is broken.

Should I eat back my exercise calories?

Only if your activity multiplier does not already include the training, which in this calculator it does. Picking 'moderate' already assumes 3–5 sessions per week, so adding tracker-estimated burn on top double-counts it — and wearable estimates for exercise calories run high. Use one method, not both.

Free Calorie Calculator — Daily Calories to Lose, Maintain or Gain

Daily calories to lose, hold or gain weight — with the deficit checked against your resting metabolism, and a week-by-week projection to your goal weight.

Energy balance, honestly stated

Body weight follows the difference between energy in and energy out. Eat less than you burn and stored energy is drawn down; eat more and it is laid in. Every diet that works — keto, fasting, calorie counting, Mediterranean, carnivore — works by moving one side of that equation, usually by making you eat less without saying so. There is no version of nutrition that escapes the accounting.

What the accounting does not tell you is that both sides are moving targets. “Energy out” falls as you get lighter and falls further because your body quietly reduces spontaneous movement in a deficit. “Energy in” is measured by you, with a phone app, against food labels that carry legal tolerances of ±20%. This is why the equation is true and calorie counting is still hard.

How the target is built

Three steps. First, resting metabolism from Mifflin-St Jeor — the best-validated general equation:

Men: BMR = 10·weight(kg) + 6.25·height(cm) − 5·age + 5 Women: BMR = 10·weight(kg) + 6.25·height(cm) − 5·age − 161

Second, multiply by an activity factor (1.2 sedentary through 1.9 extra active) to get maintenance calories, your TDEE. Third, apply the goal:

target = TDEE + (rate in kg/week × 7,700 ÷ 7) −0.5 kg/week → −550 kcal/day −1.0 kg/week → −1,100 kcal/day +0.25 kg/week → +275 kcal/day

The 7,700 kcal per kilogram (3,500 per pound) figure is where the honesty needs to start.

Why 3,500 kcal per pound is only approximately true

The number comes from a 1958 estimate: adipose tissue is roughly 87% fat by weight, fat yields about 9 kcal/g, so a pound of adipose is about 3,500 kcal. That arithmetic is fine. The problem is treating it as a conversion rate for body weight, which it is not:

Weight lost is never pure fat. Early loss is heavily glycogen and its bound water — which is why week one often shows 2 kg and week four shows 0.3 kg on the identical deficit.
The leaner you get, the more of each kilogram lost comes from lean tissue, which is far less energy-dense than fat. The effective “kcal per kg” falls.
The rule assumes your burn stays put. It does not — which is the whole reason the projection chart above bends instead of running straight.

Used as a rough planning constant over months, 7,700 kcal/kg is serviceable. Used to explain a single week, it will mislead you every time.

Rates that hold up

Goal	Rate	Daily change	Realistic for
Conservative cut	−0.25 kg / −0.5 lb per wk	−275 kcal	Already lean; protecting muscle and performance
Standard cut	−0.5 kg / −1 lb per wk	−550 kcal	Most people, most of the time
Aggressive cut	−1 kg / −2 lb per wk	−1,100 kcal	Higher starting body fat, short blocks only
Lean gain	+0.25 kg / +0.5 lb per wk	+275 kcal	Trained lifters adding mass slowly
Faster gain	+0.5 kg / +1 lb per wk	+550 kcal	Beginners and returning lifters

A useful ceiling for fat loss is about 1% of body weight per week — 0.8 kg for an 80 kg person. Below that you keep most of your muscle; above it, the share of loss coming from lean tissue climbs steeply. The other constraint is the calculator's warning: if your target falls below 1,500 kcal (men) or 1,200 kcal (women), you have picked a rate your body size cannot support.

Zigzag and refeeds

Calorie cycling — eating below target on some days and at or above it on others, for the same weekly total — is a scheduling tool, not a metabolic trick. The weekly average is what drives weight change. What cycling buys is compliance: bigger meals on training days, room for a social dinner, and a psychological reset that keeps a 16-week diet from feeling like 16 identical weeks.

Day	Flat 1,900 kcal	Zigzag, same weekly total
Mon (train)	1,900	2,150
Tue	1,900	1,700
Wed (train)	1,900	2,150
Thu	1,900	1,700
Fri (train)	1,900	2,150
Sat (social)	1,900	2,300
Sun	1,900	1,150
Weekly total	13,300	13,300

A diet break is the bigger version: one to two weeks at maintenance every couple of months. Trials comparing intermittent and continuous dieting find similar or better fat loss with breaks, largely because adherence holds up. It does not “reset your metabolism” — it resets you.

Plateaus

A genuine plateau is four weeks of flat weekly averages. Anything shorter is noise: sodium, glycogen, menstrual cycle phase, and gut contents move scale weight by a kilogram or more in either direction. When a real plateau arrives, work the list in order:

Recalculate. You are lighter than when you started, so your maintenance is lower. Re-run this calculator and the TDEE calculator at your current weight.
Re-audit logging. Portion drift is the single most common cause. Weigh everything for one week — cooking oils, sauces, drinks included.
Add movement, not deficit. An extra 3,000 steps a day is worth 100–150 kcal without touching your food, and it does not compound the fatigue.
Take a break. Two weeks at maintenance, then resume. Slower on paper, faster in practice.

Then set the macros: the macro calculator turns whatever target you settle on into protein, carbohydrate and fat grams, and the protein calculator handles the one macro that matters most in a deficit.

Free Calorie Calculator

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