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Health"How many calories should I eat?" is the most common nutrition question in the world, and the answer is genuinely personal: it depends on your size, sex, age, activity, and goal. Guessing with generic 2,000/2,500 numbers is where most calorie plans quietly fail.
This guide gives you the actual three-step calculation — BMR to TDEE to your goal target — with a worked example and the macro math behind it, so your number is yours, not an average of strangers.
Try it yourself: Get your personalized daily target in one click. Daily Calorie Calculator →
Step 1: your BMR
Start with basal metabolic rate — the calories your body burns at complete rest. Using the Mifflin-St Jeor formula:
Men: 10 × kg + 6.25 × cm − 5 × age + 5
Women: 10 × kg + 6.25 × cm − 5 × age − 161
Women: 10 × kg + 6.25 × cm − 5 × age − 161
For the full background on what BMR covers and why it matters, see BMR explained.
Step 2: multiply by activity to get TDEE
TDEE = BMR × activity factor
Use 1.2 for a sedentary desk life, 1.375 for light exercise, 1.55 for moderate training 3–5 days a week, 1.725 for hard daily training, or 1.9 for physical jobs plus training. TDEE is your maintenance number — eat exactly this and your weight stays roughly stable.
Step 3: adjust for your goal
| Goal | Adjustment | Expected pace |
|---|---|---|
| Fat loss | TDEE − 300 to 500 | ~0.5 lb (0.25 kg) per week |
| Aggressive fat loss | TDEE − 750 to 1,000 | ~1.5–2 lb per week (hard to sustain) |
| Maintenance | TDEE ± 0 | Weight stable |
| Muscle gain | TDEE + 250 to 500 | Lean gain with minimal fat |
The "3,500 calories per pound of fat" rule is an approximation — real weight loss is messier, since the body adapts — but it remains the most useful planning shortcut we have.
Full worked example
A 40-year-old man, 80 kg, 180 cm, moderately active, wants to lose fat:
- BMR = 10 × 80 + 6.25 × 180 − 5 × 40 + 5 = 800 + 1,125 − 200 + 5 = 1,730
- TDEE = 1,730 × 1.55 = 2,682
- Fat-loss target = 2,682 − 500 = ~2,180 calories/day
That 2,180 is the starting prescription, not gospel. Follow it honestly for 2–3 weeks: if weight isn't moving down, shave another 100–200 off. If energy crashes, add 100–200 back.
The macro math
Calories come from three macros with fixed energy values:
Protein: 4 kcal/g · Carbs: 4 kcal/g · Fat: 9 kcal/g
— alcohol is 7 kcal/g, fiber roughly 2 —
— alcohol is 7 kcal/g, fiber roughly 2 —
A sensible starting split for our 2,180-calorie target: protein at 1.6–2.2 g per kg of body weight (crucial in a deficit — it preserves muscle and keeps hunger down), then fill the rest with carbs and fats by preference. At 80 kg, that's ~130–175 g protein, which is 520–700 calories before carbs and fats are even counted.
Why calculators beat generic advice
The famous "2,000 calories for women, 2,500 for men" figures are planning averages, not prescriptions — a 55 kg office worker and a 95 kg construction worker live in different metabolic universes. Personalized targets also reveal surprises: many people discover their "overeating" is actually just maintenance at their size, or that their diet target was so low it was destined to fail.
The most common failure mode isn't the math — it's undercounting intake. Research consistently finds people miss 20–40% of what they eat through unmeasured oils, forgotten snacks, and generous portion estimates. A food scale for two weeks fixes more diets than any formula.
Frequently asked questions
Roughly 500 calories below your maintenance (TDEE) per day. A pound of body fat stores about 3,500 calories, so a 500-calorie daily deficit totals 3,500 over a week. Many people aim for 300–500 below TDEE; 750–1,000 deficits work faster but are harder to sustain and best discussed with a professional.
They give a solid starting point — usually within 10–15% of reality. The best approach is to use the calculated target for two to three weeks, watch the scale and measurements, then adjust up or down by 100–200 calories based on what actually happens.
No, but it helps. A calorie deficit is what causes weight loss — counting is just the most precise way to create one. Alternatives that work: eating more protein and vegetables, cutting liquid calories, fixed meal templates, or simply eating slightly less and tracking weekly weight.
The most common cause is underestimating intake — studies show people typically miss 20–40% of what they eat through forgotten snacks, unmeasured portions, and cooking oils. Track honestly for a week; if the scale still will not move, reduce the target by 100–200 calories and reassess.
Disclaimer: Calculator health content is for education only — not medical advice. Body metrics are screening tools, not diagnoses. If you have concerns about your health, speak with a qualified health professional.