How to use the calorie calculator
- Select your units, then enter your sex, age, height and weight.
- Choose the activity level that best describes a typical week.
- Your maintenance calories (total daily energy expenditure, or TDEE) appear at the top, followed by calorie targets for losing or gaining weight.
How daily calorie needs are calculated
First, the calculator estimates your basal metabolic rate (BMR) — the energy your body uses at complete rest — with the Mifflin-St Jeor equation, which research has found to be among the most accurate for healthy adults:
Then BMR is multiplied by an activity factor to estimate your total daily energy expenditure (TDEE):
| Activity level | Multiplier |
|---|---|
| Sedentary (desk job, little exercise) | 1.2 |
| Lightly active (1–3 workouts/week) | 1.375 |
| Moderately active (3–5 workouts/week) | 1.55 |
| Very active (6–7 hard workouts/week) | 1.725 |
| Extra active (physical job or 2× daily training) | 1.9 |
Example
A 30-year-old man who is 175 cm (5 ft 9 in) tall and weighs 70 kg (154 lb) has a BMR of 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 1,649 calories. If he is moderately active, his TDEE is 1,649 × 1.55 ≈ 2,556 calories per day. Eating about 2,056 calories a day (a 500-calorie deficit) would lead to roughly 1 lb (0.45 kg) of weight loss per week.
Calories for weight loss
A common rule of thumb is that a deficit of about 500 calories per day leads to roughly 1 pound of weight loss per week, because a pound of body fat stores about 3,500 calories. In reality, weight loss usually slows over time as your body adapts and your weight drops, so recalculate every few weeks.
- Aim for a moderate deficit you can sustain — losing 0.5–2 lb (0.25–1 kg) per week is generally considered safe.
- Prioritize protein and fiber to stay full and preserve muscle.
- Combine diet with strength training to keep lean mass.
- Avoid going below about 1,200 calories (women) or 1,500 calories (men) per day without medical supervision.
Calories for weight gain
To gain weight — ideally muscle — eat a small surplus of 250–500 calories per day and pair it with resistance training. A slower gain helps minimize fat gain.
Frequently asked questions
How many calories should I eat a day?
It depends on your age, sex, size and activity level. Many adults need roughly 1,600–2,400 calories (women) or 2,000–3,000 calories (men) per day to maintain weight. Use the calculator for a personalized estimate.
What is TDEE?
TDEE stands for total daily energy expenditure — the total calories you burn in a day, including your basal metabolism, digestion and all physical activity. Eating at your TDEE maintains your weight.
How many calories should I cut to lose weight?
A deficit of about 500 calories per day typically results in about 1 pound (0.45 kg) of weight loss per week. Larger deficits lead to faster loss but are harder to sustain and may cost muscle.
Which formula does this calorie calculator use?
It uses the Mifflin-St Jeor equation to estimate basal metabolic rate, then multiplies by a standard activity factor. Studies have found Mifflin-St Jeor to be one of the most accurate equations for healthy adults.
Why am I not losing weight on my calorie target?
Calculators give estimates, and individual metabolism varies. Portion sizes are also easy to underestimate. Track your intake and weight for 2–3 weeks, then adjust your calories by 100–200 per day based on real results.
This calculator provides general information only and is not a substitute for professional medical advice, diagnosis or treatment. Always consult a doctor or other qualified health provider about your individual situation.
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