Calorie Calculator

The number you actually eat against

A 30-year-old man, 180 cm, 80 kg, moderately active burns about 2,759 calories a day. To maintain his weight he eats that. To lose weight at a sustainable rate he eats around 2,259 — a 500-calorie deficit. To gain, he eats roughly 3,259.

Those three figures are the whole of calorie planning, and they all derive from one quantity: total daily energy expenditure. Getting TDEE approximately right matters far more than any decision about which foods to eat, because a deficit that is too aggressive fails through hunger and muscle loss, while one that is too small fails through invisibility.

Daily expenditure has four components. Basal metabolic rate — organ function at rest — is 60–70% of it. Physical activity (deliberate exercise) is usually only 15–30%. NEAT, the energy spent on unstructured movement like walking, standing and fidgeting, varies enormously between individuals. And the thermic effect of food, the energy used digesting what you eat, accounts for roughly 10%, which is higher for protein than for fat or carbohydrate.

How the target is built

Three steps, each feeding the next.

Step 1 — BMR, via the Mifflin-St Jeor equation (1990):

Men: (10 × kg) + (6.25 × cm) − (5 × age) + 5 Women: (10 × kg) + (6.25 × cm) − (5 × age) − 161

Step 2 — TDEE = BMR × activity multiplier:

• Sedentary (desk job, minimal exercise) — 1.2
• Lightly active (light exercise 1–3 days a week) — 1.375
• Moderately active (moderate exercise 3–5 days) — 1.55
• Very active (hard exercise 6–7 days) — 1.725
• Extremely active (physical job, or twice-daily training) — 1.9

Step 3 — apply your goal:

Target = TDEE − deficit (to lose), TDEE (to maintain), or TDEE + surplus (to gain).

The conventional 500-calorie figure comes from the estimate that a kilogram of body fat stores roughly 7,700 calories, so a 500-a-day deficit predicts about 0.45 kg a week. That is a model, not a law — real losses run slower than predicted because expenditure falls as body mass falls, and because adherence is never perfect.

Working it through

Male, 80 kg, 180 cm, 30, moderately active, maintaining.

BMR: (10 × 80) + (6.25 × 180) − (5 × 30) + 5 = 800 + 1,125 − 150 + 5 = 1,780.

TDEE: 1,780 × 1.55 = 2,759 calories.

That is the maintenance figure. Now the goals:

• Lose at a 500 deficit: 2,259 calories, predicting roughly 0.45 kg a week
• Maintain: 2,759
• Gain at a 500 surplus: 3,259

What the activity level does. Same person, same body, different multiplier:

• Sedentary: 1,780 × 1.2 = 2,136
• Lightly active: 2,448
• Moderately active: 2,759
• Very active: 3,071
• Extremely active: 3,382

A spread of 1,246 calories — larger than the effect of almost any other input. Someone who describes a desk job with three gym sessions as "very active" will set a maintenance target some 300 calories above their true one and wonder why the deficit produces nothing. When in doubt, choose the lower level and let the scale correct you.

Protein is worth setting alongside the calorie figure. In a deficit, adequate protein is what preserves muscle while fat is lost; roughly 1.6 to 2.2 g per kilogram of body weight is the range most evidence supports for people training while losing. For the 80 kg example that is about 128–176 g a day.

When to use this

Starting a deliberate weight change, so the target is anchored to your body rather than a generic 1,200 or 2,000.

When progress stalls. Expenditure falls as weight falls, so a target set 8 kg ago may now be maintenance. Recalculate every 4–5 kg.

Before a training block, to set a modest surplus — 250–500 calories is usually enough; larger surpluses add fat faster than muscle.

To calibrate expectations. Seeing that a large restaurant meal can approach a full day's allowance is more useful than any general advice about eating well.

Reading the result

The target is a starting estimate with roughly ±10% uncertainty inherited from the BMR equation, plus whatever error sits in your activity multiplier. Treat it as a hypothesis: eat at it for two to three weeks, weigh yourself consistently under the same conditions, and take the weekly average rather than daily readings, which swing with fluid, salt and digestion.

If weight moves as predicted, the estimate was right. If it does not, adjust by 100–200 calories and repeat. Your own trend data is more accurate than any equation, and after a month you no longer need the calculator.

Two floors worth respecting: do not eat below your BMR, and as a general guide not below roughly 1,500 calories for men or 1,200 for women without clinical supervision. Very low intakes cause muscle loss, nutrient deficiencies, hormonal disruption and metabolic adaptation, and they are strongly associated with regaining the weight afterwards.

This is general information, not medical or dietary advice. Anyone who is pregnant or breastfeeding, has diabetes, thyroid disease, PCOS, kidney disease or any history of disordered eating should work with a doctor or registered dietitian rather than from a calculator.

Where calorie targets go wrong

Overstating activity. The largest single source of error, and it always works against you.

Chasing an aggressive deficit. A 1,000-calorie deficit is not twice as good as 500; it is roughly twice as likely to be abandoned, and it costs more muscle.

Not recalculating after losing weight. Plateaus are usually stale maintenance figures, not broken metabolisms.

Under-recording intake. Cooking oil, sauces, drinks and untracked bites routinely account for several hundred calories a day. Studies consistently find people underestimate intake by 20% or more.

Eating back exercise calories. Activity is already inside your multiplier, and fitness-tracker burn estimates are generous. Adding them again quietly erases the deficit.

Ignoring protein and strength training. A deficit without either loses a substantial share of weight as muscle, which lowers BMR further and makes maintenance harder afterwards.

Judging progress daily. Body weight fluctuates by a kilogram or more day to day for reasons unrelated to fat. Only the multi-week trend means anything. ## Applying this to an Indian diet

Calorie targets are universal; the foods they are spent on are not. A few reference points make an Indian plate easier to plan against.

Staples carry more than people expect. One medium chapati made with 30 g of atta is roughly 110–120 calories before ghee; a katori of cooked rice is about 135–150. Three chapatis and a katori of rice is already near 500 calories before any dal or sabzi. A masala dosa runs 250–400 depending on size and oil, and two idlis with sambar around 200–250.

Cooking fat is the largest untracked variable. A tablespoon of oil or ghee is about 120 calories, and a typical home-cooked sabzi or dal for four uses two to three tablespoons. Restaurant and takeaway food uses considerably more — this is usually the single biggest gap between what people log and what they eat.

Liquid calories add up quietly. Chai with sugar and full-fat milk is 60–100 calories a cup; four cups a day is a meaningful share of a deficit. A glass of sweet lassi or a soft drink runs 150–250.

Protein is the hard part on a vegetarian Indian diet. Hitting 1.6 g per kilogram from dal, rajma, chana, paneer and curd takes deliberate planning — a katori of dal provides only about 6–7 g. Paneer, soya, curd, sprouts and supplementation where appropriate are the usual levers.

None of this requires abandoning what you eat. Measuring the cooking oil, being honest about chai, and adding a protein source to each meal typically moves a plate into a target range without changing the cuisine at all.